diff --git a/content/browser/screen_orientation/screen_orientation_dispatcher_host.cc b/content/browser/screen_orientation/screen_orientation_dispatcher_host.cc
index ccc3e228d17ea9..3bb494d93f9001 100644
--- a/content/browser/screen_orientation/screen_orientation_dispatcher_host.cc
+++ b/content/browser/screen_orientation/screen_orientation_dispatcher_host.cc
@@ -23,7 +23,7 @@ bool ScreenOrientationDispatcherHost::OnMessageReceived(
   bool handled = true;
 
   IPC_BEGIN_MESSAGE_MAP(ScreenOrientationDispatcherHost, message)
-    IPC_MESSAGE_HANDLER(ScreenOrientationHostMsg_Lock, OnLockRequest)
+    IPC_MESSAGE_HANDLER(ScreenOrientationHostMsg_LockRequest, OnLockRequest)
     IPC_MESSAGE_HANDLER(ScreenOrientationHostMsg_Unlock, OnUnlockRequest)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
@@ -42,10 +42,20 @@ void ScreenOrientationDispatcherHost::SetProviderForTests(
 }
 
 void ScreenOrientationDispatcherHost::OnLockRequest(
-    blink::WebScreenOrientationLockType orientation) {
-  if (!provider_.get())
+    blink::WebScreenOrientationLockType orientation,
+    int request_id) {
+  if (!provider_) {
+    Send(new ScreenOrientationMsg_LockError(
+         request_id,
+         blink::WebLockOrientationCallback::ErrorTypeNotAvailable));
     return;
+  }
 
+  // TODO(mlamouri): pass real values.
+  Send(new ScreenOrientationMsg_LockSuccess(
+       request_id,
+       0,
+       blink::WebScreenOrientationPortraitPrimary));
   provider_->LockOrientation(orientation);
 }
 
diff --git a/content/browser/screen_orientation/screen_orientation_dispatcher_host.h b/content/browser/screen_orientation/screen_orientation_dispatcher_host.h
index 401a9e0349bb07..363c08c6ec13cf 100644
--- a/content/browser/screen_orientation/screen_orientation_dispatcher_host.h
+++ b/content/browser/screen_orientation/screen_orientation_dispatcher_host.h
@@ -28,10 +28,12 @@ class CONTENT_EXPORT ScreenOrientationDispatcherHost
 
   void SetProviderForTests(ScreenOrientationProvider* provider);
 
- private:
+ protected:
   virtual ~ScreenOrientationDispatcherHost();
 
-  void OnLockRequest(blink::WebScreenOrientationLockType orientations);
+ private:
+  void OnLockRequest(blink::WebScreenOrientationLockType orientation,
+                     int request_id);
   void OnUnlockRequest();
 
   static ScreenOrientationProvider* CreateProvider();
diff --git a/content/browser/screen_orientation/screen_orientation_dispatcher_host_unittest.cc b/content/browser/screen_orientation/screen_orientation_dispatcher_host_unittest.cc
index 67f81de005e450..b652413d4cbc76 100644
--- a/content/browser/screen_orientation/screen_orientation_dispatcher_host_unittest.cc
+++ b/content/browser/screen_orientation/screen_orientation_dispatcher_host_unittest.cc
@@ -7,7 +7,12 @@
 #include "content/browser/screen_orientation/screen_orientation_dispatcher_host.h"
 #include "content/browser/screen_orientation/screen_orientation_provider.h"
 #include "content/common/screen_orientation_messages.h"
+#include "content/public/browser/browser_context.h"
+#include "content/public/test/mock_render_process_host.h"
+#include "content/public/test/test_browser_context.h"
+#include "content/public/test/test_browser_thread_bundle.h"
 #include "content/public/test/test_utils.h"
+#include "ipc/ipc_test_sink.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace content {
@@ -21,7 +26,6 @@ class MockScreenOrientationProvider : public ScreenOrientationProvider {
   virtual void LockOrientation(blink::WebScreenOrientationLockType orientation)
       OVERRIDE {
     orientation_ = orientation;
-
   }
 
   virtual void UnlockOrientation() OVERRIDE {
@@ -45,12 +49,32 @@ class MockScreenOrientationProvider : public ScreenOrientationProvider {
   DISALLOW_COPY_AND_ASSIGN(MockScreenOrientationProvider);
 };
 
+class ScreenOrientationDispatcherHostWithSink FINAL :
+    public ScreenOrientationDispatcherHost {
+ public:
+  explicit ScreenOrientationDispatcherHostWithSink(IPC::TestSink* sink)
+      : ScreenOrientationDispatcherHost() , sink_(sink) {}
+
+  virtual bool Send(IPC::Message* message) OVERRIDE {
+    return sink_->Send(message);
+  }
+
+ private:
+  virtual ~ScreenOrientationDispatcherHostWithSink() { }
+
+  IPC::TestSink* sink_;
+};
+
 class ScreenOrientationDispatcherHostTest : public testing::Test {
  protected:
+  virtual ScreenOrientationDispatcherHost* CreateDispatcher() {
+    return new ScreenOrientationDispatcherHost();
+  }
+
   virtual void SetUp() OVERRIDE {
     provider_ = new MockScreenOrientationProvider();
 
-    dispatcher_ = new ScreenOrientationDispatcherHost();
+    dispatcher_ = CreateDispatcher();
     dispatcher_->SetProviderForTests(provider_);
   }
 
@@ -59,19 +83,25 @@ class ScreenOrientationDispatcherHostTest : public testing::Test {
   scoped_refptr<ScreenOrientationDispatcherHost> dispatcher_;
 };
 
-// Test that a NULL provider is correctly handled.
-TEST_F(ScreenOrientationDispatcherHostTest, NullProvider) {
-  dispatcher_->SetProviderForTests(NULL);
+class ScreenOrientationDispatcherHostWithSinkTest :
+    public ScreenOrientationDispatcherHostTest {
+ protected:
+  virtual ScreenOrientationDispatcherHost* CreateDispatcher() OVERRIDE {
+    return new ScreenOrientationDispatcherHostWithSink(&sink_);
+  }
 
-  bool message_was_handled = dispatcher_->OnMessageReceived(
-      ScreenOrientationHostMsg_Lock(
-          blink::WebScreenOrientationLockPortraitPrimary));
-  EXPECT_TRUE(message_was_handled);
-}
+  const IPC::TestSink& sink() const {
+    return sink_;
+  }
+
+  IPC::TestSink sink_;
+};
 
 // Test that when receiving a lock message, it is correctly dispatched to the
 // ScreenOrientationProvider.
-TEST_F(ScreenOrientationDispatcherHostTest, ProviderLock) {
+// We don't actually need this to be a *WithSinkTest but otherwise the IPC
+// messages are detected as leaked.
+TEST_F(ScreenOrientationDispatcherHostWithSinkTest, ProviderLock) {
   // If we change this array, update |orientationsToTestCount| below.
   blink::WebScreenOrientationLockType orientationsToTest[] = {
     blink::WebScreenOrientationLockPortraitPrimary,
@@ -93,7 +123,7 @@ TEST_F(ScreenOrientationDispatcherHostTest, ProviderLock) {
     blink::WebScreenOrientationLockType orientation = orientationsToTest[i];
 
     message_was_handled = dispatcher_->OnMessageReceived(
-        ScreenOrientationHostMsg_Lock(orientation));
+        ScreenOrientationHostMsg_LockRequest(orientation, 0));
 
     EXPECT_TRUE(message_was_handled);
     EXPECT_EQ(orientation, provider_->orientation());
@@ -110,4 +140,45 @@ TEST_F(ScreenOrientationDispatcherHostTest, ProviderUnlock) {
     EXPECT_TRUE(provider_->unlock_called());
 }
 
+// Test that when there is no provider, a LockRequest fails with the appropriate
+// ErrorType.
+TEST_F(ScreenOrientationDispatcherHostWithSinkTest, NoProvider_LockError) {
+  dispatcher_->SetProviderForTests(NULL);
+
+  const int request_id = 3;
+  dispatcher_->OnMessageReceived(ScreenOrientationHostMsg_LockRequest(
+      blink::WebScreenOrientationLockPortraitPrimary, request_id));
+
+  EXPECT_EQ(1u, sink().message_count());
+
+  const IPC::Message* msg = sink().GetFirstMessageMatching(
+      ScreenOrientationMsg_LockError::ID);
+  EXPECT_TRUE(msg != NULL);
+
+  Tuple2<int, blink::WebLockOrientationCallback::ErrorType> params;
+  ScreenOrientationMsg_LockError::Read(msg, &params);
+  EXPECT_EQ(request_id, params.a);
+  EXPECT_EQ(blink::WebLockOrientationCallback::ErrorTypeNotAvailable, params.b);
+}
+
+// Test that when there is a provider, we always send a success response back to
+// the renderer.
+// TODO(mlamouri): we currently do not test the content of the message because
+// it currently contains dummy values.
+TEST_F(ScreenOrientationDispatcherHostWithSinkTest, WithProvider_LockSuccess) {
+  const int request_id = 42;
+  dispatcher_->OnMessageReceived(ScreenOrientationHostMsg_LockRequest(
+      blink::WebScreenOrientationLockPortraitPrimary, request_id));
+
+  EXPECT_EQ(1u, sink().message_count());
+
+  const IPC::Message* msg = sink().GetFirstMessageMatching(
+      ScreenOrientationMsg_LockSuccess::ID);
+  EXPECT_TRUE(msg != NULL);
+
+  Tuple3<int, unsigned, blink::WebScreenOrientationType> params;
+  ScreenOrientationMsg_LockSuccess::Read(msg, &params);
+  EXPECT_EQ(request_id, params.a);
+}
+
 } // namespace content
diff --git a/content/common/DEPS b/content/common/DEPS
index afbcc16c777d87..7d2d0e7e355f7d 100644
--- a/content/common/DEPS
+++ b/content/common/DEPS
@@ -21,6 +21,7 @@ include_rules = [
   "+third_party/WebKit/public/platform/WebIDBCursor.h",
   "+third_party/WebKit/public/platform/WebIDBDatabase.h",
   "+third_party/WebKit/public/platform/WebIDBTypes.h",
+  "+third_party/WebKit/public/platform/WebLockOrientationCallback.h",
   "+third_party/WebKit/public/platform/WebReferrerPolicy.h",
   "+third_party/WebKit/public/platform/WebScreenOrientationLockType.h",
   "+third_party/WebKit/public/platform/WebScreenOrientationType.h",
diff --git a/content/common/screen_orientation_messages.h b/content/common/screen_orientation_messages.h
index 9ea305727f4e7d..5a845e7d50fb63 100644
--- a/content/common/screen_orientation_messages.h
+++ b/content/common/screen_orientation_messages.h
@@ -7,6 +7,7 @@
 
 #include "content/common/content_export.h"
 #include "ipc/ipc_message_macros.h"
+#include "third_party/WebKit/public/platform/WebLockOrientationCallback.h"
 #include "third_party/WebKit/public/platform/WebScreenOrientationLockType.h"
 #include "third_party/WebKit/public/platform/WebScreenOrientationType.h"
 
@@ -21,16 +22,41 @@ IPC_ENUM_TRAITS_MIN_MAX_VALUE(blink::WebScreenOrientationType,
 IPC_ENUM_TRAITS_MIN_MAX_VALUE(blink::WebScreenOrientationLockType,
                               blink::WebScreenOrientationLockDefault,
                               blink::WebScreenOrientationLockPortrait)
+IPC_ENUM_TRAITS_MIN_MAX_VALUE(
+      blink::WebLockOrientationCallback::ErrorType,
+      blink::WebLockOrientationCallback::ErrorTypeNotAvailable,
+      blink::WebLockOrientationCallback::ErrorTypeCanceled)
 
 // The browser process informs the renderer process that the screen orientation
 // has changed. |orientation| contains the new screen orientation in degrees.
 IPC_MESSAGE_CONTROL1(ScreenOrientationMsg_OrientationChange,
                      blink::WebScreenOrientationType /* orientation */ )
 
+// The browser process' response to a ScreenOrientationHostMsg_LockRequest when
+// the lock actually succeeded. The message includes the new |angle| and |type|
+// of orientation. The |request_id| passed when receiving the request is passed
+// back so the renderer process can associate the response to the right request.
+IPC_MESSAGE_CONTROL3(ScreenOrientationMsg_LockSuccess,
+                     int, /* request_id */
+                     unsigned, /* angle */
+                     blink::WebScreenOrientationType /* type */)
+
+// The browser process' response to a ScreenOrientationHostMsg_LockRequest when
+// the lock actually failed. The message includes the |error| type. The
+// |request_id| passed when receiving the request is passed back so the renderer
+// process can associate the response to the right request.
+IPC_MESSAGE_CONTROL2(ScreenOrientationMsg_LockError,
+                     int, /* request_id */
+                     blink::WebLockOrientationCallback::ErrorType /* error */);
+
 // The renderer process requests the browser process to lock the screen
-// orientation to the specified |orientations|.
-IPC_MESSAGE_CONTROL1(ScreenOrientationHostMsg_Lock,
-                     blink::WebScreenOrientationLockType /* orientations */ )
+// orientation to the specified |orientations|. The request contains a
+// |request_id| that will have to be passed back to the renderer process when
+// notifying about a success or error (see ScreenOrientationMsg_LockError and
+// ScreenOrientationMsg_LockSuccess).
+IPC_MESSAGE_CONTROL2(ScreenOrientationHostMsg_LockRequest,
+                     blink::WebScreenOrientationLockType, /* orientation */
+                     int /* request_id */)
 
 // The renderer process requests the browser process to unlock the screen
 // orientation.
diff --git a/content/renderer/renderer_webkitplatformsupport_impl.cc b/content/renderer/renderer_webkitplatformsupport_impl.cc
index 5f9f398fc7633f..cd8628f4fa9183 100644
--- a/content/renderer/renderer_webkitplatformsupport_impl.cc
+++ b/content/renderer/renderer_webkitplatformsupport_impl.cc
@@ -1126,6 +1126,13 @@ void RendererWebKitPlatformSupportImpl::cancelVibration() {
 
 //------------------------------------------------------------------------------
 
+void RendererWebKitPlatformSupportImpl::EnsureScreenOrientationDispatcher() {
+  if (screen_orientation_dispatcher_)
+    return;
+
+  screen_orientation_dispatcher_.reset(new ScreenOrientationDispatcher());
+}
+
 void RendererWebKitPlatformSupportImpl::setScreenOrientationListener(
     blink::WebScreenOrientationListener* listener) {
   if (RenderThreadImpl::current() &&
@@ -1138,22 +1145,23 @@ void RendererWebKitPlatformSupportImpl::setScreenOrientationListener(
     return;
   }
 
-  if (!screen_orientation_dispatcher_) {
-    screen_orientation_dispatcher_.reset(
-        new ScreenOrientationDispatcher(RenderThread::Get()));
-  }
 
+  EnsureScreenOrientationDispatcher();
   screen_orientation_dispatcher_->setListener(listener);
 }
 
 void RendererWebKitPlatformSupportImpl::lockOrientation(
-    blink::WebScreenOrientationLockType orientation) {
+    blink::WebScreenOrientationLockType orientation,
+    blink::WebLockOrientationCallback* callback) {
   if (RenderThreadImpl::current() &&
       RenderThreadImpl::current()->layout_test_mode()) {
     g_test_screen_orientation_controller.Get().UpdateLock(orientation);
     return;
   }
-  RenderThread::Get()->Send(new ScreenOrientationHostMsg_Lock(orientation));
+
+  EnsureScreenOrientationDispatcher();
+  screen_orientation_dispatcher_->LockOrientation(
+      orientation, scoped_ptr<blink::WebLockOrientationCallback>(callback));
 }
 
 void RendererWebKitPlatformSupportImpl::unlockOrientation() {
@@ -1162,7 +1170,9 @@ void RendererWebKitPlatformSupportImpl::unlockOrientation() {
     g_test_screen_orientation_controller.Get().ResetLock();
     return;
   }
-  RenderThread::Get()->Send(new ScreenOrientationHostMsg_Unlock);
+
+  EnsureScreenOrientationDispatcher();
+  screen_orientation_dispatcher_->UnlockOrientation();
 }
 
 // static
diff --git a/content/renderer/renderer_webkitplatformsupport_impl.h b/content/renderer/renderer_webkitplatformsupport_impl.h
index 725a8ec902c3ef..0dfb4dc2b7cd52 100644
--- a/content/renderer/renderer_webkitplatformsupport_impl.h
+++ b/content/renderer/renderer_webkitplatformsupport_impl.h
@@ -148,7 +148,8 @@ class CONTENT_EXPORT RendererWebKitPlatformSupportImpl
   virtual void cancelVibration();
   virtual void setScreenOrientationListener(
       blink::WebScreenOrientationListener*);
-  virtual void lockOrientation(blink::WebScreenOrientationLockType);
+  virtual void lockOrientation(blink::WebScreenOrientationLockType,
+                               blink::WebLockOrientationCallback*);
   virtual void unlockOrientation();
   virtual void setBatteryStatusListener(
       blink::WebBatteryStatusListener* listener);
@@ -196,6 +197,7 @@ class CONTENT_EXPORT RendererWebKitPlatformSupportImpl
 
  private:
   bool CheckPreparsedJsCachingEnabled() const;
+  void EnsureScreenOrientationDispatcher();
 
   scoped_ptr<RendererClipboardClient> clipboard_client_;
   scoped_ptr<WebClipboardImpl> clipboard_;
diff --git a/content/renderer/screen_orientation/screen_orientation_dispatcher.cc b/content/renderer/screen_orientation/screen_orientation_dispatcher.cc
index 3416ec50a01a8c..280f9c79a55812 100644
--- a/content/renderer/screen_orientation/screen_orientation_dispatcher.cc
+++ b/content/renderer/screen_orientation/screen_orientation_dispatcher.cc
@@ -10,10 +10,12 @@
 
 namespace content {
 
-ScreenOrientationDispatcher::ScreenOrientationDispatcher(
-    RenderThread* thread)
-  : listener_(NULL) {
-    thread->AddObserver(this);
+ScreenOrientationDispatcher::ScreenOrientationDispatcher()
+    : listener_(NULL) {
+  RenderThread::Get()->AddObserver(this);
+}
+
+ScreenOrientationDispatcher::~ScreenOrientationDispatcher() {
 }
 
 bool ScreenOrientationDispatcher::OnControlMessageReceived(
@@ -23,6 +25,10 @@ bool ScreenOrientationDispatcher::OnControlMessageReceived(
   IPC_BEGIN_MESSAGE_MAP(ScreenOrientationDispatcher, message)
     IPC_MESSAGE_HANDLER(ScreenOrientationMsg_OrientationChange,
                         OnOrientationChange)
+    IPC_MESSAGE_HANDLER(ScreenOrientationMsg_LockSuccess,
+                        OnLockSuccess)
+    IPC_MESSAGE_HANDLER(ScreenOrientationMsg_LockError,
+                        OnLockError)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
 
@@ -37,9 +43,56 @@ void ScreenOrientationDispatcher::OnOrientationChange(
   listener_->didChangeScreenOrientation(orientation);
 }
 
+void ScreenOrientationDispatcher::OnLockSuccess(
+    int request_id,
+    unsigned angle,
+    blink::WebScreenOrientationType orientation) {
+  blink::WebLockOrientationCallback* callback =
+      pending_callbacks_.Lookup(request_id);
+  if (!callback)
+    return;
+  callback->onSuccess(angle, orientation);
+  pending_callbacks_.Remove(request_id);
+}
+
+void ScreenOrientationDispatcher::OnLockError(
+    int request_id,
+    blink::WebLockOrientationCallback::ErrorType error) {
+  blink::WebLockOrientationCallback* callback =
+      pending_callbacks_.Lookup(request_id);
+  if (!callback)
+    return;
+  callback->onError(error);
+  pending_callbacks_.Remove(request_id);
+}
+
 void ScreenOrientationDispatcher::setListener(
     blink::WebScreenOrientationListener* listener) {
   listener_ = listener;
 }
 
+void ScreenOrientationDispatcher::CancelPendingLocks() {
+  for (CallbackMap::Iterator<blink::WebLockOrientationCallback>
+       iterator(&pending_callbacks_); !iterator.IsAtEnd(); iterator.Advance()) {
+    iterator.GetCurrentValue()->onError(
+        blink::WebLockOrientationCallback::ErrorTypeCanceled);
+    pending_callbacks_.Remove(iterator.GetCurrentKey());
+  }
+}
+
+void ScreenOrientationDispatcher::LockOrientation(
+    blink::WebScreenOrientationLockType orientation,
+    scoped_ptr<blink::WebLockOrientationCallback> callback) {
+  CancelPendingLocks();
+
+  int request_id = pending_callbacks_.Add(callback.release());
+  RenderThread::Get()->Send(
+      new ScreenOrientationHostMsg_LockRequest(orientation, request_id));
+}
+
+void ScreenOrientationDispatcher::UnlockOrientation() {
+  CancelPendingLocks();
+  RenderThread::Get()->Send(new ScreenOrientationHostMsg_Unlock);
+}
+
 }  // namespace content
diff --git a/content/renderer/screen_orientation/screen_orientation_dispatcher.h b/content/renderer/screen_orientation/screen_orientation_dispatcher.h
index 5aadd6e52887de..b34e173fc8e29d 100644
--- a/content/renderer/screen_orientation/screen_orientation_dispatcher.h
+++ b/content/renderer/screen_orientation/screen_orientation_dispatcher.h
@@ -5,8 +5,12 @@
 #ifndef CONTENT_RENDERER_SCREEN_ORIENTATION_SCREEN_ORIENTATION_DISPATCHER_H_
 #define CONTENT_RENDERER_SCREEN_ORIENTATION_SCREEN_ORIENTATION_DISPATCHER_H_
 
+#include "base/id_map.h"
 #include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
 #include "content/public/renderer/render_process_observer.h"
+#include "third_party/WebKit/public/platform/WebLockOrientationCallback.h"
+#include "third_party/WebKit/public/platform/WebScreenOrientationLockType.h"
 #include "third_party/WebKit/public/platform/WebScreenOrientationType.h"
 
 namespace blink {
@@ -15,26 +19,49 @@ class WebScreenOrientationListener;
 
 namespace content {
 
-class RenderThread;
-
 // ScreenOrientationDispatcher listens to message from the browser process and
-// dispatch the orientation change ones to the WebScreenOrientationListener.
+// dispatch the orientation change ones to the WebScreenOrientationListener. It
+// also does the bridge between the browser process and Blink with regards to
+// lock orientation request and the handling of WebLockOrientationCallback.
 class CONTENT_EXPORT ScreenOrientationDispatcher
     : public RenderProcessObserver {
  public:
-  explicit ScreenOrientationDispatcher(RenderThread*);
-  virtual ~ScreenOrientationDispatcher() {}
+  ScreenOrientationDispatcher();
+  virtual ~ScreenOrientationDispatcher();
 
   // RenderProcessObserver
   virtual bool OnControlMessageReceived(const IPC::Message& message) OVERRIDE;
 
   void setListener(blink::WebScreenOrientationListener* listener);
 
+  // The |callback| is owned by ScreenOrientationDispatcher. It will be assigned
+  // to |pending_callbacks_| that will delete it when the entry will be removed
+  // from the map.
+  void LockOrientation(blink::WebScreenOrientationLockType orientation,
+                       scoped_ptr<blink::WebLockOrientationCallback> callback);
+
+  void UnlockOrientation();
+
  private:
   void OnOrientationChange(blink::WebScreenOrientationType orientation);
+  void OnLockSuccess(int request_id,
+                     unsigned angle,
+                     blink::WebScreenOrientationType orientation);
+  void OnLockError(int request_id,
+                   blink::WebLockOrientationCallback::ErrorType error);
+
+  void CancelPendingLocks();
 
   blink::WebScreenOrientationListener* listener_;
 
+  // The pending_callbacks_ map is mostly meant to have a unique ID to associate
+  // with every callback going trough the dispatcher. The map will own the
+  // pointer in the sense that it will destroy it when Remove() will be called.
+  // Furthermore, we only expect to have one callback at a time in this map,
+  // which is what IDMap was designed for.
+  typedef IDMap<blink::WebLockOrientationCallback, IDMapOwnPointer> CallbackMap;
+  CallbackMap pending_callbacks_;
+
   DISALLOW_COPY_AND_ASSIGN(ScreenOrientationDispatcher);
 };
 
diff --git a/content/renderer/screen_orientation/screen_orientation_dispatcher_unittest.cc b/content/renderer/screen_orientation/screen_orientation_dispatcher_unittest.cc
index acc12c2eb4dc35..85bcf01663896e 100644
--- a/content/renderer/screen_orientation/screen_orientation_dispatcher_unittest.cc
+++ b/content/renderer/screen_orientation/screen_orientation_dispatcher_unittest.cc
@@ -4,12 +4,15 @@
 
 #include "screen_orientation_dispatcher.h"
 
+#include <list>
+
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/common/screen_orientation_messages.h"
 #include "content/public/test/mock_render_thread.h"
 #include "content/public/test/test_utils.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/WebKit/public/platform/WebLockOrientationCallback.h"
 #include "third_party/WebKit/public/platform/WebScreenOrientationListener.h"
 
 namespace content {
@@ -38,6 +41,55 @@ class MockScreenOrientationListener :
   DISALLOW_COPY_AND_ASSIGN(MockScreenOrientationListener);
 };
 
+// MockLockOrientationCallback is an implementation of
+// WebLockOrientationCallback and takes a LockOrientationResultHolder* as a
+// parameter when being constructed. The |results_| pointer is owned by the
+// caller and not by the callback object. The intent being that as soon as the
+// callback is resolved, it will be killed so we use the
+// LockOrientationResultHolder to know in which state the callback object is at
+// any time.
+class MockLockOrientationCallback :
+    public blink::WebLockOrientationCallback {
+ public:
+  struct LockOrientationResultHolder {
+    LockOrientationResultHolder()
+        : succeeded_(false), failed_(false) {}
+
+    bool succeeded_;
+    bool failed_;
+    unsigned angle_;
+    blink::WebScreenOrientationType orientation_;
+    blink::WebLockOrientationCallback::ErrorType error_;
+  };
+
+  static scoped_ptr<blink::WebLockOrientationCallback> CreateScoped(
+      LockOrientationResultHolder* results) {
+    return scoped_ptr<blink::WebLockOrientationCallback>(
+        new MockLockOrientationCallback(results));
+  }
+
+  virtual void onSuccess(unsigned angle,
+                         blink::WebScreenOrientationType orientation) {
+    results_->succeeded_ = true;
+    results_->angle_ = angle;
+    results_->orientation_ = orientation;
+  }
+
+  virtual void onError(
+      blink::WebLockOrientationCallback::ErrorType error) {
+    results_->failed_ = true;
+    results_->error_ = error;
+  }
+
+ private:
+  explicit MockLockOrientationCallback(LockOrientationResultHolder* results)
+      : results_(results) {}
+
+  virtual ~MockLockOrientationCallback() {}
+
+  LockOrientationResultHolder* results_;
+};
+
 MockScreenOrientationListener::MockScreenOrientationListener()
     : did_change_screen_orientation_(false),
       screen_orientation_(blink::WebScreenOrientationPortraitPrimary) {
@@ -54,10 +106,20 @@ class ScreenOrientationDispatcherTest : public testing::Test {
   virtual void SetUp() OVERRIDE {
     render_thread_.reset(new MockRenderThread);
     listener_.reset(new MockScreenOrientationListener);
-    dispatcher_.reset(new ScreenOrientationDispatcher(render_thread_.get()));
+    dispatcher_.reset(new ScreenOrientationDispatcher);
     dispatcher_->setListener(listener_.get());
   }
 
+  int GetFirstLockRequestIdFromSink() {
+    const IPC::Message* msg = render_thread_->sink().GetFirstMessageMatching(
+        ScreenOrientationHostMsg_LockRequest::ID);
+    EXPECT_TRUE(msg != NULL);
+
+    Tuple2<blink::WebScreenOrientationLockType,int> params;
+    ScreenOrientationHostMsg_LockRequest::Read(msg, &params);
+    return params.b;
+  }
+
   scoped_ptr<MockRenderThread> render_thread_;
   scoped_ptr<MockScreenOrientationListener> listener_;
   scoped_ptr<ScreenOrientationDispatcher> dispatcher_;
@@ -109,4 +171,174 @@ TEST_F(ScreenOrientationDispatcherTest, ValidValues) {
                listener_->screen_orientation());
 }
 
+// Test that calling LockOrientation() followed by UnlockOrientation() cancel
+// the LockOrientation().
+TEST_F(ScreenOrientationDispatcherTest, CancelPending_Unlocking) {
+  MockLockOrientationCallback::LockOrientationResultHolder callback_results;
+  dispatcher_->LockOrientation(
+      blink::WebScreenOrientationLockPortraitPrimary,
+      MockLockOrientationCallback::CreateScoped(&callback_results));
+  dispatcher_->UnlockOrientation();
+
+  EXPECT_FALSE(callback_results.succeeded_);
+  EXPECT_TRUE(callback_results.failed_);
+  EXPECT_EQ(blink::WebLockOrientationCallback::ErrorTypeCanceled,
+            callback_results.error_);
+}
+
+// Test that calling LockOrientation() twice cancel the first LockOrientation().
+TEST_F(ScreenOrientationDispatcherTest, CancelPending_DoubleLock) {
+  MockLockOrientationCallback::LockOrientationResultHolder callback_results;
+  // We create the object to prevent leaks but never actually use it.
+  MockLockOrientationCallback::LockOrientationResultHolder callback_results2;
+
+  dispatcher_->LockOrientation(
+      blink::WebScreenOrientationLockPortraitPrimary,
+      MockLockOrientationCallback::CreateScoped(&callback_results));
+  dispatcher_->LockOrientation(
+      blink::WebScreenOrientationLockPortraitPrimary,
+      MockLockOrientationCallback::CreateScoped(&callback_results2));
+
+  EXPECT_FALSE(callback_results.succeeded_);
+  EXPECT_TRUE(callback_results.failed_);
+  EXPECT_EQ(blink::WebLockOrientationCallback::ErrorTypeCanceled,
+            callback_results.error_);
+}
+
+// Test that when a LockError message is received, the request is set as failed
+// with the correct values.
+TEST_F(ScreenOrientationDispatcherTest, LockRequest_Error) {
+  std::list<blink::WebLockOrientationCallback::ErrorType> errors;
+  errors.push_back(blink::WebLockOrientationCallback::ErrorTypeNotAvailable);
+  errors.push_back(
+      blink::WebLockOrientationCallback::ErrorTypeFullScreenRequired);
+  errors.push_back(blink::WebLockOrientationCallback::ErrorTypeCanceled);
+
+  for (std::list<blink::WebLockOrientationCallback::ErrorType>::const_iterator
+          it = errors.begin(); it != errors.end(); ++it) {
+    render_thread_->sink().ClearMessages();
+
+    MockLockOrientationCallback::LockOrientationResultHolder callback_results;
+    dispatcher_->LockOrientation(
+        blink::WebScreenOrientationLockPortraitPrimary,
+        MockLockOrientationCallback::CreateScoped(&callback_results));
+
+    int request_id = GetFirstLockRequestIdFromSink();
+    render_thread_->OnControlMessageReceived(
+        ScreenOrientationMsg_LockError(request_id, *it));
+
+    EXPECT_FALSE(callback_results.succeeded_);
+    EXPECT_TRUE(callback_results.failed_);
+    EXPECT_EQ(*it, callback_results.error_);
+  }
+}
+
+// Test that when a LockSuccess message is received, the request is set as
+// succeeded with the correct values.
+TEST_F(ScreenOrientationDispatcherTest, LockRequest_Success) {
+  struct ScreenOrientationInformation {
+    unsigned angle;
+    blink::WebScreenOrientationType type;
+  } orientations[] = {
+    { 0, blink::WebScreenOrientationPortraitPrimary },
+    { 0, blink::WebScreenOrientationLandscapePrimary },
+    { 90, blink::WebScreenOrientationPortraitSecondary },
+    { 90, blink::WebScreenOrientationLandscapePrimary }
+  };
+
+  int orientationsCount = 4;
+
+  for (int i = 0; i < orientationsCount; ++i) {
+    render_thread_->sink().ClearMessages();
+
+    MockLockOrientationCallback::LockOrientationResultHolder callback_results;
+    dispatcher_->LockOrientation(
+        blink::WebScreenOrientationLockPortraitPrimary,
+        MockLockOrientationCallback::CreateScoped(&callback_results));
+
+    int request_id = GetFirstLockRequestIdFromSink();
+    render_thread_->OnControlMessageReceived(
+        ScreenOrientationMsg_LockSuccess(request_id,
+                                         orientations[i].angle,
+                                         orientations[i].type));
+
+    EXPECT_TRUE(callback_results.succeeded_);
+    EXPECT_FALSE(callback_results.failed_);
+    EXPECT_EQ(orientations[i].angle, callback_results.angle_);
+    EXPECT_EQ(orientations[i].type, callback_results.orientation_);
+  }
+}
+
+// Test an edge case: a LockSuccess is received but it matches no pending
+// callback.
+TEST_F(ScreenOrientationDispatcherTest, SuccessForUnknownRequest) {
+  MockLockOrientationCallback::LockOrientationResultHolder callback_results;
+  dispatcher_->LockOrientation(
+      blink::WebScreenOrientationLockPortraitPrimary,
+      MockLockOrientationCallback::CreateScoped(&callback_results));
+
+  int request_id = GetFirstLockRequestIdFromSink();
+  render_thread_->OnControlMessageReceived(ScreenOrientationMsg_LockSuccess(
+      request_id + 1,
+      90,
+      blink::WebScreenOrientationLandscapePrimary));
+
+  EXPECT_FALSE(callback_results.succeeded_);
+  EXPECT_FALSE(callback_results.failed_);
+}
+
+// Test an edge case: a LockError is received but it matches no pending
+// callback.
+TEST_F(ScreenOrientationDispatcherTest, ErrorForUnknownRequest) {
+  MockLockOrientationCallback::LockOrientationResultHolder callback_results;
+  dispatcher_->LockOrientation(
+      blink::WebScreenOrientationLockPortraitPrimary,
+      MockLockOrientationCallback::CreateScoped(&callback_results));
+
+  int request_id = GetFirstLockRequestIdFromSink();
+  render_thread_->OnControlMessageReceived(ScreenOrientationMsg_LockError(
+      request_id + 1,
+      blink::WebLockOrientationCallback::ErrorTypeCanceled));
+
+  EXPECT_FALSE(callback_results.succeeded_);
+  EXPECT_FALSE(callback_results.failed_);
+}
+
+// Test the following scenario:
+// - request1 is received by the dispatcher;
+// - request2 is received by the dispatcher;
+// - request1 is rejected;
+// - request1 success response is received.
+// Expected: request1 is still rejected, request2 has not been set as succeeded.
+TEST_F(ScreenOrientationDispatcherTest, RaceScenario) {
+  MockLockOrientationCallback::LockOrientationResultHolder callback_results1;
+  MockLockOrientationCallback::LockOrientationResultHolder callback_results2;
+
+  dispatcher_->LockOrientation(
+      blink::WebScreenOrientationLockPortraitPrimary,
+      MockLockOrientationCallback::CreateScoped(&callback_results1));
+  int request_id1 = GetFirstLockRequestIdFromSink();
+
+  dispatcher_->LockOrientation(
+      blink::WebScreenOrientationLockLandscapePrimary,
+      MockLockOrientationCallback::CreateScoped(&callback_results2));
+
+  // callback_results1 must be rejected, tested in CancelPending_DoubleLock.
+
+  render_thread_->OnControlMessageReceived(ScreenOrientationMsg_LockSuccess(
+      request_id1,
+      0,
+      blink::WebScreenOrientationPortraitPrimary));
+
+  // First request is still rejected.
+  EXPECT_FALSE(callback_results1.succeeded_);
+  EXPECT_TRUE(callback_results1.failed_);
+  EXPECT_EQ(blink::WebLockOrientationCallback::ErrorTypeCanceled,
+            callback_results1.error_);
+
+  // Second request is still pending.
+  EXPECT_FALSE(callback_results2.succeeded_);
+  EXPECT_FALSE(callback_results2.failed_);
+}
+
 }  // namespace content