Add flag for drawing layers to screen with Ganesh

cc/base/switches.cc

Index: cc/base/switches.cc
diff --git a/cc/base/switches.cc b/cc/base/switches.cc
index cf2e6c5ddc4809ff4bb3ad21690886242a14cf87..63fcbaa99051e6e97573e3babb783e921108efeb 100644
--- a/cc/base/switches.cc
+++ b/cc/base/switches.cc
@@ -26,6 +26,10 @@ const char kDisableColorEstimator[] = "disable-color-estimator";
 // Overrides the kEnableImplSidePainting flag.
 const char kDisableImplSidePainting[] = "disable-impl-side-painting";
 
+// For any layers that can get drawn directly to screen, draw them with Ganesh.
+// Only valid with gl rendering / threaded compositing / impl-side painting.
+const char kDrawLayersWithGanesh[] = "draw-layers-with-ganesh";
+
 // Paint content on the compositor thread instead of the main thread.
 const char kEnableImplSidePainting[] = "enable-impl-side-painting";