[devtools] Add a command to emulate the default background color.

third_party/WebKit/Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 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 354 matching lines @@
       m_tabsToLinks(false),
       m_layerTreeView(nullptr),
       m_rootLayer(nullptr),
       m_rootGraphicsLayer(nullptr),
       m_visualViewportContainerLayer(nullptr),
       m_matchesHeuristicsForGpuRasterization(false),
       m_flingModifier(0),
       m_flingSourceDevice(WebGestureDeviceUninitialized),
       m_fullscreenController(FullscreenController::create(this)),
       m_baseBackgroundColor(Color::white),
+      m_baseBackgroundColorOverride(Color::transparent),
       m_backgroundColorOverride(Color::transparent),
       m_zoomFactorOverride(0),
       m_userGestureObserved(false),
       m_shouldDispatchFirstVisuallyNonEmptyLayout(false),
       m_shouldDispatchFirstLayoutAfterFinishedParsing(false),
       m_shouldDispatchFirstLayoutAfterFinishedLoading(false),
       m_displayMode(WebDisplayModeBrowser),
       m_elasticOverscroll(FloatSize()),
       m_mutator(nullptr),
       m_scheduler(WTF::wrapUnique(Platform::current()
@@ skipping 3185 matching lines @@
 
 bool WebViewImpl::isTransparent() const {
   return m_isTransparent;
 }
 
 WebInputMethodControllerImpl* WebViewImpl::getActiveWebInputMethodController()
     const {
   return WebInputMethodControllerImpl::fromFrame(focusedLocalFrameInWidget());
 }
 
+Color WebViewImpl::baseBackgroundColor() const {
+  return alphaChannel(m_baseBackgroundColorOverride)
+             ? m_baseBackgroundColorOverride
+             : m_baseBackgroundColor;
+}
+
 void WebViewImpl::setBaseBackgroundColor(WebColor color) {
   if (m_baseBackgroundColor == color)
     return;
 
   m_baseBackgroundColor = color;
+  updateBaseBackgroundColor();
+}
 
+void WebViewImpl::setBaseBackgroundColorOverride(WebColor color) {
+  m_baseBackgroundColorOverride = color;
+  if (mainFrameImpl()) {
+    // Force lifecycle update to ensure we're good to call
+    // FrameView::setBaseBackgroundColor().
+    mainFrameImpl()
+        ->frame()
+        ->view()
+        ->updateLifecycleToCompositingCleanPlusScrolling();
+  }
+  updateBaseBackgroundColor();
+}
+
+void WebViewImpl::updateBaseBackgroundColor() {
+  Color color = baseBackgroundColor();
   if (m_page->mainFrame() && m_page->mainFrame()->isLocalFrame())
     m_page->deprecatedLocalMainFrame()->view()->setBaseBackgroundColor(color);
 }
 
 void WebViewImpl::setIsActive(bool active) {
   if (page())
     page()->focusController().setActive(active);
 }
 
 bool WebViewImpl::isActive() const {
@@ skipping 598 matching lines @@
   if (focusedFrame->localFrameRoot() != mainFrameImpl()->frame())
     return nullptr;
   return focusedFrame;
 }
 
 LocalFrame* WebViewImpl::focusedLocalFrameAvailableForIme() const {
   return m_imeAcceptEvents ? focusedLocalFrameInWidget() : nullptr;
 }
 
 }  // namespace blink