[testing] Move test vsync waiters to their own TUs (#14456)

This move makes it easier to add more vsync waiters.

Author: iskakaushik

ci/licenses_golden/licenses_flutter

@@ -568,6 +568,8 @@ FILE: ../../../flutter/shell/common/surface.cc
 FILE: ../../../flutter/shell/common/surface.h
 FILE: ../../../flutter/shell/common/switches.cc
 FILE: ../../../flutter/shell/common/switches.h
+FILE: ../../../flutter/shell/common/test_vsync_waiters.cc
+FILE: ../../../flutter/shell/common/test_vsync_waiters.h
 FILE: ../../../flutter/shell/common/thread_host.cc
 FILE: ../../../flutter/shell/common/thread_host.h
 FILE: ../../../flutter/shell/common/vsync_waiter.cc

shell/common/BUILD.gn

@@ -166,6 +166,8 @@ if (current_toolchain == host_toolchain) {
       "shell_test.cc",
       "shell_test.h",
       "shell_unittests.cc",
+      "test_vsync_waiters.cc",
+      "test_vsync_waiters.h",
     ]
 
     deps = [

shell/common/shell_test.cc

@@ -289,46 +289,6 @@ void ShellTest::AddNativeCallback(std::string name,
   native_resolver_->AddNativeCallback(std::move(name), callback);
 }
 
-void ShellTestVsyncClock::SimulateVSync() {
-  std::scoped_lock lock(mutex_);
-  if (vsync_issued_ >= vsync_promised_.size()) {
-    vsync_promised_.emplace_back();
-  }
-  FML_CHECK(vsync_issued_ < vsync_promised_.size());
-  vsync_promised_[vsync_issued_].set_value(vsync_issued_);
-  vsync_issued_ += 1;
-}
-
-std::future<int> ShellTestVsyncClock::NextVSync() {
-  std::scoped_lock lock(mutex_);
-  vsync_promised_.emplace_back();
-  return vsync_promised_.back().get_future();
-}
-
-void ShellTestVsyncWaiter::AwaitVSync() {
-  FML_DCHECK(task_runners_.GetUITaskRunner()->RunsTasksOnCurrentThread());
-  auto vsync_future = clock_.NextVSync();
-
-  auto async_wait = std::async([&vsync_future, this]() {
-    vsync_future.wait();
-
-    // Post the `FireCallback` to the Platform thread so earlier Platform tasks
-    // (specifically, the `VSyncFlush` call) will be finished before
-    // `FireCallback` is executed. This is only needed for our unit tests.
-    //
-    // Without this, the repeated VSYNC signals in `VSyncFlush` may start both
-    // the current frame in the UI thread and the next frame in the secondary
-    // callback (both of them are waiting for VSYNCs). That breaks the unit
-    // test's assumption that each frame's VSYNC must be issued by different
-    // `VSyncFlush` call (which resets the `will_draw_new_frame` bit).
-    //
-    // For example, HandlesActualIphoneXsInputEvents will fail without this.
-    task_runners_.GetPlatformTaskRunner()->PostTask([this]() {
-      FireCallback(fml::TimePoint::Now(), fml::TimePoint::Now());
-    });
-  });
-}
-
 ShellTestPlatformView::ShellTestPlatformView(PlatformView::Delegate& delegate,
                                              TaskRunners task_runners,
                                              bool simulate_vsync)

shell/common/shell_test.h

@@ -13,6 +13,7 @@
 #include "flutter/lib/ui/window/platform_message.h"
 #include "flutter/shell/common/run_configuration.h"
 #include "flutter/shell/common/shell.h"
+#include "flutter/shell/common/test_vsync_waiters.h"
 #include "flutter/shell/common/thread_host.h"
 #include "flutter/shell/gpu/gpu_surface_gl_delegate.h"
 #include "flutter/testing/test_dart_native_resolver.h"
@@ -88,32 +89,6 @@ class ShellTest : public ThreadTest {
   FML_DISALLOW_COPY_AND_ASSIGN(ShellTest);
 };
 
-class ShellTestVsyncClock {
- public:
-  /// Simulate that a vsync signal is triggered.
-  void SimulateVSync();
-
-  /// A future that will return the index the next vsync signal.
-  std::future<int> NextVSync();
-
- private:
-  std::mutex mutex_;
-  std::vector<std::promise<int>> vsync_promised_;
-  size_t vsync_issued_ = 0;
-};
-
-class ShellTestVsyncWaiter : public VsyncWaiter {
- public:
-  ShellTestVsyncWaiter(TaskRunners task_runners, ShellTestVsyncClock& clock)
-      : VsyncWaiter(std::move(task_runners)), clock_(clock) {}
-
- protected:
-  void AwaitVSync() override;
-
- private:
-  ShellTestVsyncClock& clock_;
-};
-
 class ShellTestPlatformView : public PlatformView, public GPUSurfaceGLDelegate {
  public:
   ShellTestPlatformView(PlatformView::Delegate& delegate,

shell/common/test_vsync_waiters.cc

@@ -0,0 +1,61 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#define FML_USED_ON_EMBEDDER
+
+#include "flutter/shell/common/shell_test.h"
+
+#include "flutter/flow/layers/layer_tree.h"
+#include "flutter/flow/layers/transform_layer.h"
+#include "flutter/fml/make_copyable.h"
+#include "flutter/fml/mapping.h"
+#include "flutter/runtime/dart_vm.h"
+#include "flutter/shell/gpu/gpu_surface_gl.h"
+#include "flutter/testing/testing.h"
+
+namespace flutter {
+namespace testing {
+
+void ShellTestVsyncClock::SimulateVSync() {
+  std::scoped_lock lock(mutex_);
+  if (vsync_issued_ >= vsync_promised_.size()) {
+    vsync_promised_.emplace_back();
+  }
+  FML_CHECK(vsync_issued_ < vsync_promised_.size());
+  vsync_promised_[vsync_issued_].set_value(vsync_issued_);
+  vsync_issued_ += 1;
+}
+
+std::future<int> ShellTestVsyncClock::NextVSync() {
+  std::scoped_lock lock(mutex_);
+  vsync_promised_.emplace_back();
+  return vsync_promised_.back().get_future();
+}
+
+void ShellTestVsyncWaiter::AwaitVSync() {
+  FML_DCHECK(task_runners_.GetUITaskRunner()->RunsTasksOnCurrentThread());
+  auto vsync_future = clock_.NextVSync();
+
+  auto async_wait = std::async([&vsync_future, this]() {
+    vsync_future.wait();
+
+    // Post the `FireCallback` to the Platform thread so earlier Platform tasks
+    // (specifically, the `VSyncFlush` call) will be finished before
+    // `FireCallback` is executed. This is only needed for our unit tests.
+    //
+    // Without this, the repeated VSYNC signals in `VSyncFlush` may start both
+    // the current frame in the UI thread and the next frame in the secondary
+    // callback (both of them are waiting for VSYNCs). That breaks the unit
+    // test's assumption that each frame's VSYNC must be issued by different
+    // `VSyncFlush` call (which resets the `will_draw_new_frame` bit).
+    //
+    // For example, HandlesActualIphoneXsInputEvents will fail without this.
+    task_runners_.GetPlatformTaskRunner()->PostTask([this]() {
+      FireCallback(fml::TimePoint::Now(), fml::TimePoint::Now());
+    });
+  });
+}
+
+}  // namespace testing
+}  // namespace flutter

shell/common/test_vsync_waiters.h

@@ -0,0 +1,44 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#define FML_USED_ON_EMBEDDER
+
+#ifndef FLUTTER_SHELL_COMMON_TEST_VSYNC_WAITERS_H_
+#define FLUTTER_SHELL_COMMON_TEST_VSYNC_WAITERS_H_
+
+#include "flutter/shell/common/shell.h"
+
+namespace flutter {
+namespace testing {
+
+class ShellTestVsyncClock {
+ public:
+  /// Simulate that a vsync signal is triggered.
+  void SimulateVSync();
+
+  /// A future that will return the index the next vsync signal.
+  std::future<int> NextVSync();
+
+ private:
+  std::mutex mutex_;
+  std::vector<std::promise<int>> vsync_promised_;
+  size_t vsync_issued_ = 0;
+};
+
+class ShellTestVsyncWaiter : public VsyncWaiter {
+ public:
+  ShellTestVsyncWaiter(TaskRunners task_runners, ShellTestVsyncClock& clock)
+      : VsyncWaiter(std::move(task_runners)), clock_(clock) {}
+
+ protected:
+  void AwaitVSync() override;
+
+ private:
+  ShellTestVsyncClock& clock_;
+};
+
+}  // namespace testing
+}  // namespace flutter
+
+#endif  // FLUTTER_SHELL_COMMON_TEST_VSYNC_WAITERS_H_