Refactor cc scrollbar layers to separate solid-color vs desktop.

cc/base/switches.cc

 // 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.
 
 #include "cc/base/switches.h"
 
 #include "base/command_line.h"
 
 namespace cc {
 namespace switches {
@@ skipping 113 matching lines @@
 // is not considered to be occluding the pixels behind it.
 const char kShowNonOccludingRects[] = "show-nonoccluding-rects";
 const char kUIShowNonOccludingRects[] = "ui-show-nonoccluding-rects";
 
 // Enable the codepath that uses images within TileManager.
 const char kUseMapImage[] = "use-map-image";
 
 // Prevents the layer tree unit tests from timing out.
 const char kCCLayerTreeTestNoTimeout[] = "cc-layer-tree-test-no-timeout";
 
+// Enables overlay scrollbars on Aura or Linux. Does nothing on Mac.
+const char kEnableOverlayScrollbars[] = "enable-overlay-scrollbars";
+
+bool AreOverlayScrollbarsEnabled() {
+  return CommandLine::ForCurrentProcess()->HasSwitch(
+      cc::switches::kEnableOverlayScrollbars);
+}
+
 bool IsImplSidePaintingEnabled() {
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
   if (command_line.HasSwitch(cc::switches::kDisableImplSidePainting))
     return false;
   else if (command_line.HasSwitch(cc::switches::kEnableImplSidePainting))
     return true;
 
 #if defined(OS_ANDROID)
   return true;
 #else
   return false;
 #endif
 }
 
 }  // namespace switches
 }  // namespace cc