Move some work from backend onClear to base class clear

src/gpu/GrCommandBuilder.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrCommandBuilder_DEFINED
 #define GrCommandBuilder_DEFINED
 
@@ skipping 31 matching lines @@
                                  GrBufferedDrawTarget*,
                                  const GrPathProcessor*,
                                  const GrPathRange*,
                                  const void*,
                                  GrDrawTarget::PathIndexType,
                                  const float transformValues[],
                                  GrDrawTarget::PathTransformType ,
                                  int,
                                  const GrStencilSettings&,
                                  const GrDrawTarget::PipelineInfo&) = 0;
-    virtual Cmd* recordClear(const SkIRect* rect,
+    virtual Cmd* recordClear(const SkIRect& rect,
                              GrColor,
-                             bool canIgnoreRect,
                              GrRenderTarget*);
     virtual Cmd* recordCopySurface(GrSurface* dst,
                                    GrSurface* src,
                                    const SkIRect& srcRect,
                                    const SkIPoint& dstPoint);
     virtual Cmd* recordXferBarrierIfNecessary(const GrPipeline&, const GrCaps&);
 
 protected:
     typedef GrTargetCommands::DrawBatch DrawBatch;
     typedef GrTargetCommands::StencilPath StencilPath;
     typedef GrTargetCommands::DrawPath DrawPath;
     typedef GrTargetCommands::DrawPaths DrawPaths;
     typedef GrTargetCommands::Clear Clear;
     typedef GrTargetCommands::ClearStencilClip ClearStencilClip;
     typedef GrTargetCommands::CopySurface CopySurface;
     typedef GrTargetCommands::XferBarrier XferBarrier;
 
     GrCommandBuilder(GrGpu* gpu) : fCommands(gpu) {}
 
     GrTargetCommands::CmdBuffer* cmdBuffer() { return fCommands.cmdBuffer(); }
     GrBatchTarget* batchTarget() { return fCommands.batchTarget(); }
 
 private:
     GrTargetCommands fCommands;
 
 };
 
 #endif