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

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 2324 matching lines @@
 
 bool FrameView::hasOpaqueBackground() const {
   return !m_baseBackgroundColor.hasAlpha();
 }
 
 Color FrameView::baseBackgroundColor() const {
   return m_baseBackgroundColor;
 }
 
 void FrameView::setBaseBackgroundColor(const Color& backgroundColor) {
+  if (m_baseBackgroundColor == backgroundColor)
+    return;
+
   m_baseBackgroundColor = backgroundColor;
 
   if (!layoutViewItem().isNull() &&
       layoutViewItem().layer()->hasCompositedLayerMapping()) {
     CompositedLayerMapping* compositedLayerMapping =
         layoutViewItem().layer()->compositedLayerMapping();
     compositedLayerMapping->updateContentsOpaque();
     if (compositedLayerMapping->mainGraphicsLayer())
       compositedLayerMapping->mainGraphicsLayer()->setNeedsDisplay();
   }
@@ skipping 2914 matching lines @@
 void FrameView::setAnimationHost(
     std::unique_ptr<CompositorAnimationHost> host) {
   m_animationHost = std::move(host);
 }
 
 LayoutUnit FrameView::caretWidth() const {
   return LayoutUnit(getHostWindow()->windowToViewportScalar(1));
 }
 
 }  // namespace blink