Workaround for PowerVR clear issue.

src/gpu/GrGpu.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 GrGpu_DEFINED
 #define GrGpu_DEFINED
 
@@ skipping 248 matching lines @@
      * @param buffer        memory to read pixels from
      * @param rowBytes      number of bytes between consecutive rows. Zero
      *                      means rows are tightly packed.
      */
     bool writeTexturePixels(GrTexture* texture,
                             int left, int top, int width, int height,
                             GrPixelConfig config, const void* buffer,
                             size_t rowBytes);
 
     // GrDrawTarget overrides
-    virtual void clear(const SkIRect* rect, GrColor color, bool canIgnoreRect,
-                       GrRenderTarget* renderTarget) SK_OVERRIDE;
-
     virtual void clearStencilClip(const SkIRect& rect,
                                   bool insideClip,
                                   GrRenderTarget* renderTarget = NULL) SK_OVERRIDE;
 
     // After the client interacts directly with the 3D context state the GrGpu
     // must resync its internal state and assumptions about 3D context state.
     // Each time this occurs the GrGpu bumps a timestamp.
     // state of the 3D context
     // At 10 resets / frame and 60fps a 64bit timestamp will overflow in about
     // a billion years.
@@ skipping 85 matching lines @@
     SkAutoTDelete<GrPathRendering> fPathRendering;
 
 private:
     // GrDrawTarget overrides
     virtual bool onReserveVertexSpace(size_t vertexSize, int vertexCount, void** vertices) SK_OVERRIDE;
     virtual bool onReserveIndexSpace(int indexCount, void** indices) SK_OVERRIDE;
     virtual void releaseReservedVertexSpace() SK_OVERRIDE;
     virtual void releaseReservedIndexSpace() SK_OVERRIDE;
     virtual void geometrySourceWillPush() SK_OVERRIDE;
     virtual void geometrySourceWillPop(const GeometrySrcState& restoredState) SK_OVERRIDE;
-
+    virtual void onClear(const SkIRect* rect, GrColor color, bool canIgnoreRect,
+                         GrRenderTarget* renderTarget) SK_OVERRIDE;
 
     // called when the 3D context state is unknown. Subclass should emit any
     // assumed 3D context state and dirty any state cache.
     virtual void onResetContext(uint32_t resetBits) = 0;
 
     // overridden by backend-specific derived class to create objects.
     virtual GrTexture* onCreateTexture(const GrSurfaceDesc& desc,
                                        const void* srcData,
                                        size_t rowBytes) = 0;
     virtual GrTexture* onCreateCompressedTexture(const GrSurfaceDesc& desc,
                                                  const void* srcData) = 0;
     virtual GrTexture* onWrapBackendTexture(const GrBackendTextureDesc&) = 0;
     virtual GrRenderTarget* onWrapBackendRenderTarget(const GrBackendRenderTargetDesc&) = 0;
     virtual GrVertexBuffer* onCreateVertexBuffer(size_t size, bool dynamic) = 0;
     virtual GrIndexBuffer* onCreateIndexBuffer(size_t size, bool dynamic) = 0;
 
-    // overridden by backend-specific derived class to perform the clear and
-    // clearRect. NULL rect means clear whole target. If canIgnoreRect is
-    // true, it is okay to perform a full clear instead of a partial clear
-    virtual void onClear(GrRenderTarget*, const SkIRect* rect, GrColor color,
-                         bool canIgnoreRect) = 0;
+    // overridden by backend-specific derived class to perform the clear.
+    virtual void onGpuClear(GrRenderTarget*, const SkIRect* rect, GrColor color,
+                            bool canIgnoreRect) = 0;
 
 
     // Overridden by backend specific classes to perform a clear of the stencil clip bits.  This is
     // ONLY used by the the clip target
     virtual void onClearStencilClip(GrRenderTarget*,
                                     const SkIRect& rect,
                                     bool insideClip) = 0;
 
     // overridden by backend-specific derived class to perform the draw call.
     virtual void onGpuDraw(const DrawInfo&) = 0;
@@ skipping 73 matching lines @@
     // counts number of uses of vertex/index pool in the geometry stack
     int                                                                 fVertexPoolUseCnt;
     int                                                                 fIndexPoolUseCnt;
     // these are mutable so they can be created on-demand
     mutable GrIndexBuffer*                                              fQuadIndexBuffer;
 
     typedef GrClipTarget INHERITED;
 };
 
 #endif