diff --git a/chrome/browser/resources/pdf/pdf.js b/chrome/browser/resources/pdf/pdf.js
index 18b008da3d6ddb..0616c8df40ab1d 100644
--- a/chrome/browser/resources/pdf/pdf.js
+++ b/chrome/browser/resources/pdf/pdf.js
@@ -235,14 +235,18 @@ PDFViewer.prototype = {
         }
         return;
       case 219:  // left bracket.
-        this.plugin_.postMessage({
-          type: 'rotateCounterclockwise',
-        });
+        if (e.ctrlKey) {
+          this.plugin_.postMessage({
+            type: 'rotateCounterclockwise',
+          });
+        }
         return;
       case 221:  // right bracket.
-        this.plugin_.postMessage({
-          type: 'rotateClockwise',
-        });
+        if (e.ctrlKey) {
+          this.plugin_.postMessage({
+            type: 'rotateClockwise',
+          });
+        }
         return;
     }
   },
diff --git a/pdf/instance.cc b/pdf/instance.cc
index 6a68400d6ee4e1..a71d071ba9cb7f 100644
--- a/pdf/instance.cc
+++ b/pdf/instance.cc
@@ -587,21 +587,26 @@ bool Instance::HandleInputEvent(const pp::InputEvent& event) {
     }
   }
 
-  if (event.GetType() == PP_INPUTEVENT_TYPE_KEYDOWN &&
-      event.GetModifiers() & kDefaultKeyModifier) {
+  if (event.GetType() == PP_INPUTEVENT_TYPE_KEYDOWN) {
     pp::KeyboardInputEvent keyboard_event(event);
-    switch (keyboard_event.GetKeyCode()) {
-      case 'A':
-        engine_->SelectAll();
-        return true;
-      case ui::VKEY_OEM_4:
-        // Left bracket.
-        engine_->RotateCounterclockwise();
-        return true;
-      case ui::VKEY_OEM_6:
-        // Right bracket.
-        engine_->RotateClockwise();
-        return true;
+    const uint32 modifier = event.GetModifiers();
+    if (modifier & kDefaultKeyModifier) {
+      switch (keyboard_event.GetKeyCode()) {
+        case 'A':
+          engine_->SelectAll();
+          return true;
+      }
+    } else if (modifier & PP_INPUTEVENT_MODIFIER_CONTROLKEY) {
+      switch (keyboard_event.GetKeyCode()) {
+        case ui::VKEY_OEM_4:
+          // Left bracket.
+          engine_->RotateCounterclockwise();
+          return true;
+        case ui::VKEY_OEM_6:
+          // Right bracket.
+          engine_->RotateClockwise();
+          return true;
+      }
     }
   }