Make rendering timeouts work even if paint data received early

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 323c0b810fd32f4d2ac3c1f3e9618bc8cbc2af73..446080e133396781e6bee98408659dddb5b0a8a8 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -197,6 +197,7 @@ RenderWidgetHostImpl::RenderWidgetHostImpl(RenderWidgetHostDelegate* delegate,
       allow_privileged_mouse_lock_(false),
       has_touch_handler_(false),
       is_in_gesture_scroll_(false),
+      received_paint_after_load_(false),
       next_browser_snapshot_id_(1),
       owned_by_render_frame_host_(false),
       is_focused_(false),
@@ -920,6 +921,14 @@ void RenderWidgetHostImpl::StopHangMonitorTimeout() {
 }
 
 void RenderWidgetHostImpl::StartNewContentRenderingTimeout() {
+  // It is possible for a compositor frame to arrive before the browser
+  // is notified about the page have been committed, in which case

[Charlie Reis, 2015/09/30 20:36:19]

nit: about the page being committed

[kenrb, 2015/09/30 21:25:02]

Done.

+  // no timer is necessary.
+  if (received_paint_after_load_) {
+    received_paint_after_load_ = false;
+    return;
+  }
+
   if (new_content_rendering_timeout_)
     new_content_rendering_timeout_->Start(new_content_rendering_delay_);
 }
@@ -929,6 +938,14 @@ void RenderWidgetHostImpl::StopNewContentRenderingTimeout() {
     new_content_rendering_timeout_->Stop();
 }
 
+void RenderWidgetHostImpl::OnFirstPaintAfterLoad() {
+  if (new_content_rendering_timeout_->IsRunning()) {
+    StopNewContentRenderingTimeout();
+  } else {
+    received_paint_after_load_ = true;
+  }
+}
+
 void RenderWidgetHostImpl::ForwardMouseEvent(const WebMouseEvent& mouse_event) {
   ForwardMouseEventWithLatencyInfo(mouse_event, ui::LatencyInfo());
 }
@@ -1522,8 +1539,6 @@ bool RenderWidgetHostImpl::OnSwapCompositorFrame(
   // chrome/browser/extensions/api/cast_streaming/performance_test.cc
   TRACE_EVENT0("test_fps,benchmark", "OnSwapCompositorFrame");
 
-  StopNewContentRenderingTimeout();
-
   ViewHostMsg_SwapCompositorFrame::Param param;
   if (!ViewHostMsg_SwapCompositorFrame::Read(&message, &param))
     return false;