cc: Remove code for drawing checkerboard quads, it's not used.

cc/quads/draw_quad.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_QUADS_DRAW_QUAD_H_
 #define CC_QUADS_DRAW_QUAD_H_
 
 #include "base/callback.h"
 #include "cc/base/cc_export.h"
 #include "cc/base/resource_id.h"
@@ skipping 17 matching lines @@
 // the "content space", which is the arbitrary space in which the quad's
 // geometry is defined (generally related to the layer that produced the quad,
 // e.g. the geometry space for PictureLayerImpls or the layer's coordinate space
 // for most other layers). There is also the "target space", which is the space,
 // in "physical" pixels, of the render target where the quads is drawn. The
 // quad's transform maps the content space to the target space.
 class CC_EXPORT DrawQuad {
  public:
   enum Material {
     INVALID,
-    CHECKERBOARD,
     DEBUG_BORDER,
     IO_SURFACE_CONTENT,
     PICTURE_CONTENT,
     RENDER_PASS,
     SOLID_COLOR,
     STREAM_VIDEO_CONTENT,
     SURFACE_CONTENT,
     TEXTURE_CONTENT,
     TILED_CONTENT,
     YUV_VIDEO_CONTENT,
@@ skipping 88 matching lines @@
               const gfx::Rect& rect,
               const gfx::Rect& opaque_rect,
               const gfx::Rect& visible_rect,
               bool needs_blending);
   virtual void ExtendValue(base::trace_event::TracedValue* value) const = 0;
 };
 
 }  // namespace cc
 
 #endif  // CC_QUADS_DRAW_QUAD_H_