Added preliminary support for tile rasterization with Ganesh

cc/resources/raster_mode.cc

Index: cc/resources/raster_mode.cc
diff --git a/cc/resources/raster_mode.cc b/cc/resources/raster_mode.cc
index 47d6344c97d8b41731aa169a4c8a3ded2723575f..9fb58e77495b27d29b9fa58619ffe1eab6e92136 100644
--- a/cc/resources/raster_mode.cc
+++ b/cc/resources/raster_mode.cc
@@ -21,6 +21,9 @@ scoped_ptr<base::Value> RasterModeAsValue(RasterMode raster_mode) {
     case LOW_QUALITY_RASTER_MODE:
       return scoped_ptr<base::Value>(
           base::Value::CreateStringValue("LOW_QUALITY_RASTER_MODE"));
+    case GPU_RASTER_MODE:
+      return scoped_ptr<base::Value>(
+          base::Value::CreateStringValue("GPU_RASTER_MODE"));
     default:
       NOTREACHED() << "Unrecognized RasterMode value " << raster_mode;
       return scoped_ptr<base::Value>(