Implement canComputeFastBounds() for image filters.

src/effects/SkColorFilterImageFilter.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 "SkColorFilterImageFilter.h"
 #include "SkBitmap.h"
 #include "SkCanvas.h"
@@ skipping 80 matching lines @@
     SkASSERT(1 == this->countInputs());
     if (!this->cropRectIsSet()) {
         if (filter) {
             *filter = SkRef(fColorFilter);
         }
         return true;
     }
     return false;
 }
 
+bool SkColorFilterImageFilter::affectsTransparentBlack() const {
+    return fColorFilter->affectsTransparentBlack();
+}
+
 #ifndef SK_IGNORE_TO_STRING
 void SkColorFilterImageFilter::toString(SkString* str) const {
     str->appendf("SkColorFilterImageFilter: (");
 
     str->appendf("input: (");
 
     if (this->getInput(0)) {
         this->getInput(0)->toString(str);
     }
 
     str->appendf(") color filter: ");
     fColorFilter->toString(str);
 
     str->append(")");
 }
 #endif