Fix GPU displacement with expanding crop rects.

src/effects/SkDisplacementMapEffect.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkDisplacementMapEffect.h"
 #include "SkReadBuffer.h"
 #include "SkWriteBuffer.h"
@@ skipping 366 matching lines @@
     }
     if (!bounds.intersect(displBounds)) {
         return false;
     }
     GrTexture* color = colorBM.getTexture();
     GrTexture* displacement = displacementBM.getTexture();
     GrContext* context = color->getContext();
 
     GrTextureDesc desc;
     desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
-    desc.fWidth = colorBM.width();
-    desc.fHeight = colorBM.height();
+    desc.fWidth = bounds.width();
+    desc.fHeight = bounds.height();
     desc.fConfig = kSkia8888_GrPixelConfig;
 
     GrAutoScratchTexture ast(context, desc);
     SkAutoTUnref<GrTexture> dst(ast.detach());
 
     GrContext::AutoRenderTarget art(context, dst->asRenderTarget());
 
     SkVector scale = SkVector::Make(fScale, fScale);
     ctx.ctm().mapVectors(&scale, 1);
 
     GrPaint paint;
     SkMatrix offsetMatrix = GrEffect::MakeDivByTextureWHMatrix(displacement);
     offsetMatrix.preTranslate(SkIntToScalar(colorOffset.fX - displacementOffset.fX),
                               SkIntToScalar(colorOffset.fY - displacementOffset.fY));
 
     paint.addColorEffect(
         GrDisplacementMapEffect::Create(fXChannelSelector,
                                         fYChannelSelector,
                                         scale,
                                         displacement,
                                         offsetMatrix,
                                         color))->unref();
     SkIRect colorBounds = bounds;
     colorBounds.offset(-colorOffset);
+    GrContext::AutoMatrix am;
+    am.setIdentity(context);
     SkMatrix matrix;
     matrix.setTranslate(-SkIntToScalar(colorBounds.x()),
                         -SkIntToScalar(colorBounds.y()));
     context->concatMatrix(matrix);
     context->drawRect(paint, SkRect::Make(colorBounds));
     offset->fX = bounds.left();
     offset->fY = bounds.top();
     WrapTexture(dst, bounds.width(), bounds.height(), result);
     return true;
 }
@@ skipping 179 matching lines @@
                                                         const GrGLCaps&) {
     const GrDisplacementMapEffect& displacementMap =
         drawEffect.castEffect<GrDisplacementMapEffect>();
 
     EffectKey xKey = displacementMap.xChannelSelector();
     EffectKey yKey = displacementMap.yChannelSelector() << kChannelSelectorKeyBits;
 
     return xKey | yKey;
 }
 #endif