Define a --force-gpu-rasterization flag

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 1d5d5be765356c811576c94184089b09b142f2cc..a7cbd6fbf8636fd1d839cf08c506984cf33f707e 100644
--- a/android_webview/lib/main/aw_main_delegate.cc
+++ b/android_webview/lib/main/aw_main_delegate.cc
@@ -20,7 +20,6 @@
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/thread_restrictions.h"
-#include "cc/base/switches.h"
 #include "content/public/browser/browser_main_runner.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/common/content_switches.h"
@@ -57,7 +56,8 @@ bool AwMainDelegate::BasicStartupComplete(int* exit_code) {
 
   CommandLine* cl = CommandLine::ForCurrentProcess();
   cl->AppendSwitch(switches::kEnableBeginFrameScheduling);
-  cl->AppendSwitch(cc::switches::kEnableMapImage);
+  cl->AppendSwitch(switches::kEnableMapImage);
+  cl->AppendSwitch(switches::kEnableImplSidePainting);
 
   // WebView uses the Android system's scrollbars and overscroll glow.
   cl->AppendSwitch(switches::kHideScrollbars);