Added a command-line flag to enable h/w accelerated rendering of content layers.

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
===================================================================
--- chrome/common/chrome_switches.cc	(revision 80690)
+++ chrome/common/chrome_switches.cc	(working copy)
@@ -389,6 +389,12 @@
 // Enable gpu-accelerated 2d canvas.
 const char kEnableAccelerated2dCanvas[]     = "enable-accelerated-2d-canvas";
 
+// Enable hardware accelerated page drawing.
+// Please note that this flag is honored only if chromium is compiled with
+// SKIA_GPU flag, which can be enabled by setting use_skia_gpu variable to 1
+// in build/features_override.gypi.
+const char kEnableAcceleratedDrawing[] = "enable-accelerated-drawing";
+
 // Enables the hardware acceleration of plugins.
 const char kEnableAcceleratedPlugins[]      = "enable-accelerated-plugins";