Add toString methods to SkImageFilter-derived classes

include/effects/SkDisplacementMapEffect.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkDisplacementMapEffect_DEFINED
 #define SkDisplacementMapEffect_DEFINED
 
@@ skipping 30 matching lines @@
 
     virtual bool onFilterBounds(const SkIRect& src, const SkMatrix&,
                                 SkIRect* dst) const SK_OVERRIDE;
 
 #if SK_SUPPORT_GPU
     virtual bool canFilterImageGPU() const SK_OVERRIDE { return true; }
     virtual bool filterImageGPU(Proxy* proxy, const SkBitmap& src, const Context& ctx,
                                 SkBitmap* result, SkIPoint* offset) const SK_OVERRIDE;
 #endif
 
+    SK_TO_STRING_OVERRIDE()
+
 protected:
     SkDisplacementMapEffect(ChannelSelectorType xChannelSelector,
                             ChannelSelectorType yChannelSelector,
                             SkScalar scale, SkImageFilter* inputs[2],
                             const CropRect* cropRect,
                             uint32_t uniqueID);
     virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
 
 private:
     ChannelSelectorType fXChannelSelector;
     ChannelSelectorType fYChannelSelector;
     SkScalar fScale;
     typedef SkImageFilter INHERITED;
     const SkImageFilter* getDisplacementInput() const { return getInput(0); }
     const SkImageFilter* getColorInput() const { return getInput(1); }
 };
 
 #endif