Enable disabling WebCore::GraphicsContext in telemetry.

cc/layers/content_layer_client.h

Index: cc/layers/content_layer_client.h
diff --git a/cc/layers/content_layer_client.h b/cc/layers/content_layer_client.h
index 6a77dab532e29c9b70f6075e2bc3068edc247380..0eb9b18a8c987db84fd3aecb52f9b57c2e445e81 100644
--- a/cc/layers/content_layer_client.h
+++ b/cc/layers/content_layer_client.h
@@ -18,9 +18,17 @@ namespace cc {
 
 class CC_EXPORT ContentLayerClient {
  public:
-  virtual void PaintContents(SkCanvas* canvas,
-                             const gfx::Rect& clip,
-                             gfx::RectF* opaque) = 0;
+  enum GraphicsContextStatus {
+    GraphicsContextEnabled,

[Sami, 2014/05/01 16:32:53]

nit: Swap the order of these two so that enabled = 1?

[danakj, 2014/05/01 17:07:11]

+1

[Stephen Chennney, 2014/05/01 19:12:26]

Done.
And also switched to Chromium style for enums.

+    GraphicsContextDisabled
+  };
+
+  virtual void PaintContents(
+      SkCanvas* canvas,
+      const gfx::Rect& clip,
+      gfx::RectF* opaque,
+      GraphicsContextStatus
+          graphics_context_state = GraphicsContextEnabled) = 0;

[Sami, 2014/05/01 16:32:53]

Chromium style prohibits default parameters, but it looks like this is always
passed in so we could just make it required?

[Stephen Chennney, 2014/05/01 19:12:26]

Done.

Means changing more files, but that's life.

 
   // Called by the content layer during the update phase.
   // If the client paints LCD text, it may want to invalidate the layer.