Move some work from backend onClear to base class clear

src/gpu/GrBufferedDrawTarget.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrBufferedDrawTarget_DEFINED
 #define GrBufferedDrawTarget_DEFINED
 
@@ skipping 78 matching lines @@
                     const PipelineInfo&) override;
     void onDrawPaths(const GrPathProcessor*,
                      const GrPathRange*,
                      const void* indices,
                      PathIndexType,
                      const float transformValues[],
                      PathTransformType,
                      int count,
                      const GrStencilSettings&,
                      const PipelineInfo&) override;
-    void onClear(const SkIRect* rect,
+    void onClear(const SkIRect& rect,
                  GrColor color,
-                 bool canIgnoreRect,
                  GrRenderTarget* renderTarget) override;
     void onCopySurface(GrSurface* dst,
                        GrSurface* src,
                        const SkIRect& srcRect,
                        const SkIPoint& dstPoint) override;
 
     // Records any trace markers for a command
     void recordTraceMarkersIfNecessary(GrTargetCommands::Cmd*);
     SkString getCmdString(int index) const {
         SkASSERT(index < fGpuCmdMarkers.count());
@@ skipping 22 matching lines @@
     SkChunkAlloc                        fPathIndexBuffer;
     SkChunkAlloc                        fPathTransformBuffer;
     SkChunkAlloc                        fPipelineBuffer;
     uint32_t                            fDrawID;
     SkAutoTUnref<State>                 fPrevState;
 
     typedef GrClipTarget INHERITED;
 };
 
 #endif