add applyFilter() to SkImage

include/core/SkImageFilter.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImageFilter_DEFINED
 #define SkImageFilter_DEFINED
 
@@ skipping 77 matching lines @@
          */
         bool applyTo(const SkIRect& imageBounds, const Context&, SkIRect* cropped) const;
 
     private:
         SkRect fRect;
         uint32_t fFlags;
     };
 
     class Proxy {
     public:
-        Proxy(SkBaseDevice* device) : fDevice(device) { }
+        virtual ~Proxy() {}
 
-        SkBaseDevice* createDevice(int width, int height);
+        virtual SkBaseDevice* createDevice(int width, int height) = 0;
+
+        // Returns true if the proxy handled the filter itself. If this returns
+        // false then the filter's code will be called.
+        virtual bool filterImage(const SkImageFilter*, const SkBitmap& src,
+                                 const SkImageFilter::Context&,
+                                 SkBitmap* result, SkIPoint* offset) = 0;
+    };
+
+    class DeviceProxy : public Proxy {
+    public:
+        DeviceProxy(SkBaseDevice* device) : fDevice(device) {}
+
+        SkBaseDevice* createDevice(int width, int height) override;
 
         // Returns true if the proxy handled the filter itself. If this returns
         // false then the filter's code will be called.
         bool filterImage(const SkImageFilter*, const SkBitmap& src, const SkImageFilter::Context&,
-                         SkBitmap* result, SkIPoint* offset);
+                                 SkBitmap* result, SkIPoint* offset) override;
 
     private:
         SkBaseDevice* fDevice;
     };
 
-
     /**
      *  Request a new (result) image to be created from the src image.
      *  If the src has no pixels (isNull()) then the request just wants to
      *  receive the config and width/height of the result.
      *
      *  The matrix is the current matrix on the canvas.
      *
      *  Offset is the amount to translate the resulting image relative to the
      *  src when it is drawn. This is an out-param.
      *
@@ skipping 270 matching lines @@
  */
 #define SK_IMAGEFILTER_UNFLATTEN_COMMON(localVar, expectedCount)    \
     Common localVar;                                                \
     do {                                                            \
         if (!localVar.unflatten(buffer, expectedCount)) {           \
             return NULL;                                            \
         }                                                           \
     } while (0)
 
 #endif