Make IsSolidColor() a property on CC scrollbar layers.

content/browser/android/content_startup_flags.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 "content/browser/android/content_startup_flags.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "cc/base/switches.h"
@@ skipping 43 matching lines @@
       switches::kEnableCompositingForFixedPosition);
   parsed_command_line->AppendSwitch(switches::kEnableAcceleratedOverflowScroll);
   parsed_command_line->AppendSwitch(
       switches::kEnableAcceleratedScrollableFrames);
   parsed_command_line->AppendSwitch(
       switches::kEnableCompositedScrollingForFrames);
 
   parsed_command_line->AppendSwitch(switches::kEnableGestureTapHighlight);
   parsed_command_line->AppendSwitch(switches::kEnablePinch);
   parsed_command_line->AppendSwitch(switches::kEnableOverscrollNotifications);
+  parsed_command_line->AppendSwitch(cc::switches::kForceSolidColorScrollbars);
+
+  std::string thickness_string(cc::switches::kSolidColorScrollbarThickness);
+  thickness_string.append("=3");

[bulach, 2013/06/28 19:55:48]

nit: maybe extract these as named constants up above?
something like:

namespace {
const char kSolidColorScrollbarThicknessValue[] = "=3";
const char kSolidColorScrollbarColorValue[] = "=0x80808080";
}  // namespace

+  parsed_command_line->AppendSwitch(thickness_string);
+
+  std::string color_string(cc::switches::kSolidColorScrollbarColor);
+  color_string.append("=0x80808080");
+  parsed_command_line->AppendSwitch(color_string);
 
   // Run the GPU service as a thread in the browser instead of as a
   // standalone process.
   parsed_command_line->AppendSwitch(switches::kInProcessGPU);
   parsed_command_line->AppendSwitch(switches::kDisableGpuShaderDiskCache);
 
   // Always use fixed layout and viewport tag.
   parsed_command_line->AppendSwitch(switches::kEnableFixedLayout);
   parsed_command_line->AppendSwitch(switches::kEnableViewport);
 
   if (!plugin_descriptor.empty()) {
     parsed_command_line->AppendSwitchNative(
       switches::kRegisterPepperPlugins, plugin_descriptor);
   }
 }
 
 }  // namespace content