Fix for crbug.com/111185.

content/browser/renderer_host/render_widget_host.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_H_
 #pragma once
 
 #include <deque>
 #include <string>
@@ skipping 515 matching lines @@
   // Indicates if the render widget host should track the render widget's size
   // as opposed to visa versa.
   void SetShouldAutoResize(bool enable);
 
  protected:
   // true if a renderer has once been valid. We use this flag to display a sad
   // tab only when we lose our renderer and not if a paint occurs during
   // initialization.
   bool renderer_initialized_;
 
+  // This value indicates how long to wait before we consider a renderer hung.
+  int hung_renderer_delay_ms_;
+
  private:
   FRIEND_TEST_ALL_PREFIXES(RenderWidgetHostTest, Resize);
   FRIEND_TEST_ALL_PREFIXES(RenderWidgetHostTest, ResizeThenCrash);
   FRIEND_TEST_ALL_PREFIXES(RenderWidgetHostTest, HiddenPaint);
   FRIEND_TEST_ALL_PREFIXES(RenderWidgetHostTest, PaintAtSize);
 
   // Tell this object to destroy itself.
   void Destroy();
 
   // Checks whether the renderer is hung and calls NotifyRendererUnresponsive
@@ skipping 83 matching lines @@
                               const gfx::Size& view_size);
 
   // Called by OnMsgInputEventAck() to process a keyboard event ack message.
   void ProcessKeyboardEventAck(int type, bool processed);
 
   // Called by OnMsgInputEventAck() to process a wheel event ack message.
   // This could result in a task being posted to allow additional wheel
   // input messages to be coalesced.
   void ProcessWheelAck(bool processed);
 
+  // These two methods are being used by the "hung renderer" monitoring
+  // mechanism. This mechanism relies on starting a timer and counting
+  // input events going to the renderer as well as the corresponding
+  // acks coming back from the renderer. The two methods below are used
+  // for counting.
+  void RecordInputEvent();
+  bool RecordInputEventAck();
+
   // True if renderer accessibility is enabled. This should only be set when a
   // screenreader is detected as it can potentially slow down Chrome.
   bool renderer_accessible_;
 
   // The View associated with the RenderViewHost. The lifetime of this object
   // is associated with the lifetime of the Render process. If the Renderer
   // crashes, its View is destroyed and this pointer becomes NULL, even though
   // render_view_host_ lives on to load another URL (creating a new View while
   // doing so).
   RenderWidgetHostView* view_;
@@ skipping 87 matching lines @@
   // itself, a paint message could already be in flight at that point.
   bool needs_repainting_on_restore_;
 
   // This is true if the renderer is currently unresponsive.
   bool is_unresponsive_;
 
   // The following value indicates a time in the future when we would consider
   // the renderer hung if it does not generate an appropriate response message.
   base::Time time_when_considered_hung_;
 
+  // This value denotes the number of input events yet to be acknowledged
+  // by the renderer.
+  int event_count_;
+
   // This timer runs to check if time_when_considered_hung_ has past.
   base::OneShotTimer<RenderWidgetHost> hung_renderer_timer_;
 
   // Flag to detect recursive calls to GetBackingStore().
   bool in_get_backing_store_;
 
   // Set when we call DidPaintRect/DidScrollRect on the view.
   bool view_being_painted_;
 
   // Used for UMA histogram logging to measure the time for a repaint view
@@ skipping 41 matching lines @@
   gfx::Point last_scroll_offset_;
 
   bool pending_mouse_lock_request_;
 
   base::WeakPtrFactory<RenderWidgetHost> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHost);
 };
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_H_