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

third_party/WebKit/Source/web/WebViewImpl.cpp

Index: third_party/WebKit/Source/web/WebViewImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebViewImpl.cpp b/third_party/WebKit/Source/web/WebViewImpl.cpp
index 5aefab4a47c2325a1980e994e7dad4e50bb1b936..8725dba24f218526c15ece8a7117e7de329be5f0 100644
--- a/third_party/WebKit/Source/web/WebViewImpl.cpp
+++ b/third_party/WebKit/Source/web/WebViewImpl.cpp
@@ -373,6 +373,7 @@ WebViewImpl::WebViewImpl(WebViewClient* client,
       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),
@@ -3572,12 +3573,29 @@ WebInputMethodControllerImpl* WebViewImpl::getActiveWebInputMethodController()
   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;
+  updateBaseBackgroundColor();
+}
 
+void WebViewImpl::updateBaseBackgroundColor() {
+  WebColor color = alphaChannel(m_baseBackgroundColorOverride)

[dgozman, 2017/01/26 00:04:17]

Use baseBackgroundColor().

[Eric Seckler, 2017/02/06 23:54:37]

Done.

+                       ? m_baseBackgroundColorOverride
+                       : m_baseBackgroundColor;
   if (m_page->mainFrame() && m_page->mainFrame()->isLocalFrame())
     m_page->deprecatedLocalMainFrame()->view()->setBaseBackgroundColor(color);
 }