[blink] Use early returns in baseBackgroundColor(Override) setters.

third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 284 matching lines @@
   m_backgroundColorOverride = color;
   updateLayerTreeBackgroundColor();
 }
 
 void WebFrameWidgetImpl::clearBackgroundColorOverride() {
   m_backgroundColorOverrideEnabled = false;
   updateLayerTreeBackgroundColor();
 }
 
 void WebFrameWidgetImpl::setBaseBackgroundColorOverride(WebColor color) {
+  if (m_baseBackgroundColorOverrideEnabled &&
+      m_baseBackgroundColorOverride == color) {
+    return;
+  }
+
   m_baseBackgroundColorOverrideEnabled = true;
   m_baseBackgroundColorOverride = color;
+  // Force lifecycle update to ensure we're good to call
+  // FrameView::setBaseBackgroundColor().
+  m_localRoot->frameView()->updateLifecycleToCompositingCleanPlusScrolling();
   updateBaseBackgroundColor();
 }
 
 void WebFrameWidgetImpl::clearBaseBackgroundColorOverride() {
+  if (!m_baseBackgroundColorOverrideEnabled)
+    return;
+
   m_baseBackgroundColorOverrideEnabled = false;
+  // Force lifecycle update to ensure we're good to call
+  // FrameView::setBaseBackgroundColor().
+  m_localRoot->frameView()->updateLifecycleToCompositingCleanPlusScrolling();
   updateBaseBackgroundColor();
 }
 
 void WebFrameWidgetImpl::layoutAndPaintAsync(
     WebLayoutAndPaintAsyncCallback* callback) {
   m_layerTreeView->layoutAndPaintAsync(callback);
 }
 
 void WebFrameWidgetImpl::compositeAndReadbackAsync(
     WebCompositeAndReadbackAsyncCallback* callback) {
@@ skipping 836 matching lines @@
   return nullptr;
 }
 
 LocalFrame* WebFrameWidgetImpl::focusedLocalFrameAvailableForIme() const {
   if (!m_imeAcceptEvents)
     return nullptr;
   return focusedLocalFrameInWidget();
 }
 
 }  // namespace blink