Clear renderer compositor trees if new page does not render in 4 seconds

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 36baa7d16f680e4c03d1381814a7452e3295e3ae..8f318fcb977750f8129236f15c8bce1e446e0e6b 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -629,6 +629,7 @@ bool RenderWidget::OnMessageReceived(const IPC::Message& message) {
                         OnSetViewportIntersection)
     IPC_MESSAGE_HANDLER(ViewMsg_WaitForNextFrameForTests,
                         OnWaitNextFrameForTests)
+    IPC_MESSAGE_HANDLER(ViewMsg_ClearDisplayedContent, OnClearDisplayedContent)
     IPC_MESSAGE_HANDLER(InputMsg_RequestCompositionUpdate,
                         OnRequestCompositionUpdate)
     IPC_MESSAGE_HANDLER(DragMsg_TargetDragEnter, OnDragTargetDragEnter)
@@ -2315,4 +2316,10 @@ blink::WebInputMethodController* RenderWidget::GetInputMethodController()
       ->getActiveWebInputMethodController();
 }
 
+void RenderWidget::OnClearDisplayedContent() {
+  if (compositor_) {
+    compositor_->ResetTrees();
+  }
+}
+
 }  // namespace content