aw: Enable async ondraw by default

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 53abf193dce7cbd5ba513b84cb2bc1faaa4240e9..08c9fe1fa6cec3d77a5d12f40807c60f6a8d524d 100644
--- a/android_webview/lib/main/aw_main_delegate.cc
+++ b/android_webview/lib/main/aw_main_delegate.cc
@@ -66,6 +66,9 @@ bool AwMainDelegate::BasicStartupComplete(int* exit_code) {
 
   base::CommandLine* cl = base::CommandLine::ForCurrentProcess();
 
+  // Enable async OnDraw by default. See crbug.com/636164 for progress.
+  cl->AppendSwitch(switches::kAsyncOnDrawHardware);
+
   // WebView uses the Android system's scrollbars and overscroll glow.
   cl->AppendSwitch(switches::kDisableOverscrollEdgeEffect);