[content] Fix background color update handling in RWHVAura.

content/public/browser/render_widget_host_view.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_BROWSER_RENDER_WIDGET_HOST_VIEW_H_
 #define CONTENT_PUBLIC_BROWSER_RENDER_WIDGET_HOST_VIEW_H_
 
 #include <memory>
 
 #include "base/strings/string16.h"
@@ skipping 110 matching lines @@
   // Returns true if the View's context menu is showing.
   virtual bool IsShowingContextMenu() const = 0;
 
   // Tells the View whether the context menu is showing.
   virtual void SetShowingContextMenu(bool showing) = 0;
 
   // Returns the currently selected text.
   virtual base::string16 GetSelectedText() = 0;
 
   // Subclasses should override this method to set the background color. |color|
-  // could be transparent or opaque.
+  // has to be either SK_ColorTRANSPARENT or opaque. If set to
+  // SK_ColorTRANSPARENT, the renderer's background color will be overridden to
+  // be fully transparent.
   virtual void SetBackgroundColor(SkColor color) = 0;
+  virtual SkColor background_color() const = 0;

[danakj, 2017/02/28 17:52:31]

Technically this breaks (already did) the style guide as virtuals should be
BackgroundColor() styled. But there's a billion call sites probably. If you're
adventurous it might be nice to fix it in another CL real quick.

[Eric Seckler, 2017/03/01 10:22:09]

Yeah, I was considering doing that, but it seemed the effort required to find
all call sites on all platforms (afaik code search references only work on
linux?) was larger than the benefit -.-

Do we have a tool that can help with such a change, other than trial-and-error
on the different trybots?

   // Convenience method to fill the background layer with the default color by
   // calling |SetBackgroundColor|.
-  virtual SkColor background_color() = 0;
   virtual void SetBackgroundColorToDefault() = 0;
-  virtual bool GetBackgroundOpaque() = 0;
 
   // Return value indicates whether the mouse is locked successfully or not.
   virtual bool LockMouse() = 0;
   virtual void UnlockMouse() = 0;
   // Returns true if the mouse pointer is currently locked.
   virtual bool IsMouseLocked() = 0;
 
   // Retrives the size of the viewport for the visible region. May be smaller
   // than the view size if a portion of the view is obstructed (e.g. by a
   // virtual keyboard).
@@ skipping 44 matching lines @@
   // Returns |true| if text is currently being spoken by Mac OS X.
   virtual bool IsSpeaking() const = 0;
   // Stops speaking, if it is currently in progress.
   virtual void StopSpeaking() = 0;
 #endif  // defined(OS_MACOSX)
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_RENDER_WIDGET_HOST_VIEW_H_