Workaround for PowerVR clear issue.

src/gpu/GrDrawTarget.h

Index: src/gpu/GrDrawTarget.h
diff --git a/src/gpu/GrDrawTarget.h b/src/gpu/GrDrawTarget.h
index b1f758a7316daaf620d3fa7a7a90f725d87cdc35..47b439e114aba1e13ed70ee9d90c659a369b490f 100644
--- a/src/gpu/GrDrawTarget.h
+++ b/src/gpu/GrDrawTarget.h
@@ -395,8 +395,8 @@ public:
      * rect is NULL, otherwise just the rect. If canIgnoreRect is set then the entire render target
      * can be optionally cleared.
      */
-    virtual void clear(const SkIRect* rect, GrColor color, bool canIgnoreRect,
-                       GrRenderTarget* renderTarget) = 0;
+    void clear(const SkIRect* rect, GrColor color, bool canIgnoreRect,
+               GrRenderTarget* renderTarget);
 
     /**
      * Discards the contents render target.
@@ -855,6 +855,10 @@ private:
                              const float transforms[], PathTransformType,
                              GrPathRendering::FillType, const GrDeviceCoordTexture*) = 0;
 
+    virtual void onClear(const SkIRect* rect, GrColor color, bool canIgnoreRect,
+                         GrRenderTarget* renderTarget) = 0;
+
+
     virtual void didAddGpuTraceMarker() = 0;
     virtual void didRemoveGpuTraceMarker() = 0;