Implement correct clipping for image filters.

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 237 matching lines @@
 }
 
 void SkDisplacementMapEffect::computeFastBounds(const SkRect& src, SkRect* dst) const {
     if (getColorInput()) {
         getColorInput()->computeFastBounds(src, dst);
     } else {
         *dst = src;
     }
 }
 
+bool SkDisplacementMapEffect::onFilterBounds(const SkIRect& src, const SkMatrix& ctm,
+                                   SkIRect* dst) const {
+    if (getColorInput()) {
+        return getColorInput()->filterBounds(src, ctm, dst);
+    }
+    *dst = src;
+    return true;
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 #if SK_SUPPORT_GPU
 class GrGLDisplacementMapEffect : public GrGLEffect {
 public:
     GrGLDisplacementMapEffect(const GrBackendEffectFactory& factory,
                               const GrDrawEffect& drawEffect);
     virtual ~GrGLDisplacementMapEffect();
 
     virtual void emitCode(GrGLShaderBuilder*,
@@ skipping 322 matching lines @@
                                                         const GrGLCaps&) {
     const GrDisplacementMapEffect& displacementMap =
         drawEffect.castEffect<GrDisplacementMapEffect>();
 
     EffectKey xKey = displacementMap.xChannelSelector();
     EffectKey yKey = displacementMap.yChannelSelector() << SkDisplacementMapEffect::kKeyBits;
 
     return xKey | yKey;
 }
 #endif