Remove offscreen compositor contexts.

cc/output/direct_renderer.h

Index: cc/output/direct_renderer.h
diff --git a/cc/output/direct_renderer.h b/cc/output/direct_renderer.h
index 16394c5899ac800767b3d06270e176e1d2547f1d..cace98ae315bcd903380eba3dc71f8c3e69269fa 100644
--- a/cc/output/direct_renderer.h
+++ b/cc/output/direct_renderer.h
@@ -32,7 +32,6 @@ class CC_EXPORT DirectRenderer : public Renderer {
   virtual bool HasAllocatedResourcesForTesting(RenderPass::Id id) const
       OVERRIDE;
   virtual void DrawFrame(RenderPassList* render_passes_in_draw_order,
-                         ContextProvider* offscreen_context_provider,
                          float device_scale_factor,
                          const gfx::Rect& device_viewport_rect,
                          const gfx::Rect& device_clip_rect,
@@ -53,8 +52,6 @@ class CC_EXPORT DirectRenderer : public Renderer {
     gfx::Transform projection_matrix;
     gfx::Transform window_matrix;
 
-    ContextProvider* offscreen_context_provider;
-
     bool disable_picture_quad_image_filtering;
 
     OverlayCandidateList overlay_list;