Don't allow renderTarget==NULL to GrContext::clear() and friends.

src/effects/SkMorphologyImageFilter.cpp

 /*
  * Copyright 2012 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkMorphologyImageFilter.h"
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
@@ skipping 512 matching lines @@
     if (radius.fWidth > 0) {
         GrTexture* texture = context->refScratchTexture(desc, GrContext::kApprox_ScratchTexMatch);
         if (NULL == texture) {
             return false;
         }
         GrContext::AutoRenderTarget art(context, texture->asRenderTarget());
         apply_morphology_pass(context, srcTexture, srcRect, dstRect, radius.fWidth,
                               morphType, Gr1DKernelEffect::kX_Direction);
         SkIRect clearRect = SkIRect::MakeXYWH(dstRect.fLeft, dstRect.fBottom,
                                               dstRect.width(), radius.fHeight);
-        context->clear(&clearRect, GrMorphologyEffect::kErode_MorphologyType == morphType ?
-                                   SK_ColorWHITE :
-                                   SK_ColorTRANSPARENT, false);
+        GrColor clearColor = GrMorphologyEffect::kErode_MorphologyType == morphType ?
+                                SK_ColorWHITE :
+                                SK_ColorTRANSPARENT;
+        context->clear(&clearRect, clearColor, false, texture->asRenderTarget());
         srcTexture.reset(texture);
         srcRect = dstRect;
     }
     if (radius.fHeight > 0) {
         GrTexture* texture = context->refScratchTexture(desc, GrContext::kApprox_ScratchTexMatch);
         if (NULL == texture) {
             return false;
         }
         GrContext::AutoRenderTarget art(context, texture->asRenderTarget());
         apply_morphology_pass(context, srcTexture, srcRect, dstRect, radius.fHeight,
@@ skipping 54 matching lines @@
                                          SkBitmap* result, SkIPoint* offset) const {
     return this->filterImageGPUGeneric(true, proxy, src, ctx, result, offset);
 }
 
 bool SkErodeImageFilter::filterImageGPU(Proxy* proxy, const SkBitmap& src, const Context& ctx,
                                         SkBitmap* result, SkIPoint* offset) const {
     return this->filterImageGPUGeneric(false, proxy, src, ctx, result, offset);
 }
 
 #endif