Make rendering timeouts work even if paint data received early

content/browser/renderer_host/render_widget_host_impl.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_IMPL_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_IMPL_H_
 
 #include <list>
 #include <map>
 #include <string>
@@ skipping 245 matching lines @@
   void StartHangMonitorTimeout(base::TimeDelta delay);
 
   // Stops all existing hang monitor timeouts and assumes the renderer is
   // responsive.
   void StopHangMonitorTimeout();
 
   // Starts the rendering timeout, which will clear displayed graphics if
   // a new compositor frame is not received before it expires.
   void StartNewContentRenderingTimeout();
 
-  // Stops the rendering timeout and prevents it from clearing any displayed
-  // graphics.
-  void StopNewContentRenderingTimeout();
+  // Notification that a new compositor frame has been generated following
+  // a page load. This stops |new_content_rendering_timeout_|, or prevents
+  // the timer from running if the load commit message hasn't been received
+  // yet.
+  void OnFirstPaintAfterLoad();
 
   // Forwards the given message to the renderer. These are called by the view
   // when it has received a message.
   void ForwardGestureEventWithLatencyInfo(
       const blink::WebGestureEvent& gesture_event,
       const ui::LatencyInfo& ui_latency);
   void ForwardTouchEventWithLatencyInfo(
       const blink::WebTouchEvent& touch_event,
       const ui::LatencyInfo& ui_latency);
   void ForwardMouseEventWithLatencyInfo(
@@ skipping 525 matching lines @@
 
   scoped_ptr<TouchEmulator> touch_emulator_;
 
   // Receives and handles all input events.
   scoped_ptr<InputRouter> input_router_;
 
   scoped_ptr<TimeoutMonitor> hang_monitor_timeout_;
 
   scoped_ptr<TimeoutMonitor> new_content_rendering_timeout_;
 
+  // This boolean is true if RenderWidgetHostImpl receives a compositor frame
+  // from a newly loaded page before StartNewContentRenderingTimeout() is
+  // called. This means that a paint for the new load has completed before
+  // the browser received a DidCommitProvisionalLoad message. In that case
+  // |new_content_rendering_timeout_| is not needed. The renderer will send
+  // both the FirstPaintAfterLoad and DidCommitProvisionalLoad messages after
+  // any new page navigation, it doesn't matter which is received first, and
+  // it should not be possible to interleave other navigations in between
+  // receipt of those messages (unless FirstPaintAfterLoad is prevented from
+  // being sent, in which case the timer should fire).
+  bool received_paint_after_load_;
+
 #if defined(OS_WIN)
   std::list<HWND> dummy_windows_for_activation_;
 #endif
 
   RenderWidgetHostLatencyTracker latency_tracker_;
 
   int next_browser_snapshot_id_;
   using PendingSnapshotMap = std::map<int, GetSnapshotFromBrowserCallback>;
   PendingSnapshotMap pending_browser_snapshots_;
 
   // Indicates whether a RenderFramehost has ownership, in which case this
   // object does not self destroy.
   bool owned_by_render_frame_host_;
 
   // Indicates whether this RenderWidgetHost thinks is focused. This is trying
   // to match what the renderer process knows. It is different from
   // RenderWidgetHostView::HasFocus in that in that the focus request may fail,
   // causing HasFocus to return false when is_focused_ is true.
   bool is_focused_;
 
   base::WeakPtrFactory<RenderWidgetHostImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_IMPL_H_