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

android_webview/lib/main/aw_main_delegate.cc

Index: android_webview/lib/main/aw_main_delegate.cc
diff --git a/android_webview/lib/main/aw_main_delegate.cc b/android_webview/lib/main/aw_main_delegate.cc
index 6843a748ea81445c345df649141ed2627071fc32..dec7c25161a7be83afc9376c0a923377ae5c592f 100644
--- a/android_webview/lib/main/aw_main_delegate.cc
+++ b/android_webview/lib/main/aw_main_delegate.cc
@@ -56,7 +56,9 @@ bool AwMainDelegate::BasicStartupComplete(int* exit_code) {
     cl->AppendSwitch(cc::switches::kUseMapImage);
 
   // WebView uses the Android system's scrollbars and overscroll glow.
-  cl->AppendSwitch(switches::kHideScrollbars);

[enne (OOO), 2013/08/28 18:22:08]

I don't understand what changing kHideScrollbars to kSolidColorScrollbarColor
gets you, other than churn and an untested StringToSkColor function.  I prefer
the previous version, which also keeps all the color-setting code in one place.

[wjmaclean, 2013/08/28 20:51:46]

Done.

Removed. If there's any desire to control this color via a switch that can
happen in a separate CL.

+  string hide_scrollbar_switch(cc::switches::kSolidColorScrollbarColor);
+  hide_scrollbar_switch.append("=0x00000000");
+  cl->AppendSwitch(hide_scrollbar_switch);
   cl->AppendSwitch(switches::kDisableOverscrollEdgeEffect);
 
   // Not yet secure in single-process mode.