Make SkImageFilter methods const.

include/core/SkBitmapDevice.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 SkBitmapDevice_DEFINED
 #define SkBitmapDevice_DEFINED
@@ skipping 209 matching lines @@
     */
     virtual void lockPixels() SK_OVERRIDE;
     virtual void unlockPixels() SK_OVERRIDE;
 
     /**
      *  Returns true if the device allows processing of this imagefilter. If
      *  false is returned, then the filter is ignored. This may happen for
      *  some subclasses that do not support pixel manipulations after drawing
      *  has occurred (e.g. printing). The default implementation returns true.
      */
-    virtual bool allowImageFilter(SkImageFilter*) SK_OVERRIDE;
+    virtual bool allowImageFilter(const SkImageFilter*) SK_OVERRIDE;
 
     /**
      *  Override and return true for filters that the device can handle
      *  intrinsically. Doing so means that SkCanvas will pass-through this
      *  filter to drawSprite and drawDevice (and potentially filterImage).
      *  Returning false means the SkCanvas will have apply the filter itself,
      *  and just pass the resulting image to the device.
      */
-    virtual bool canHandleImageFilter(SkImageFilter*) SK_OVERRIDE;
+    virtual bool canHandleImageFilter(const SkImageFilter*) SK_OVERRIDE;
 
     /**
      *  Related (but not required) to canHandleImageFilter, this method returns
      *  true if the device could apply the filter to the src bitmap and return
      *  the result (and updates offset as needed).
      *  If the device does not recognize or support this filter,
      *  it just returns false and leaves result and offset unchanged.
      */
-    virtual bool filterImage(SkImageFilter*, const SkBitmap&, const SkMatrix&,
+    virtual bool filterImage(const SkImageFilter*, const SkBitmap&, const SkMatrix&,
                              SkBitmap* result, SkIPoint* offset) SK_OVERRIDE;
 
 private:
     friend class SkCanvas;
     friend struct DeviceCM; //for setMatrixClip
     friend class SkDraw;
     friend class SkDrawIter;
     friend class SkDeviceFilteredPaint;
     friend class SkDeviceImageFilterProxy;
 
@@ skipping 19 matching lines @@
     virtual void flush() SK_OVERRIDE {}
 
     virtual SkSurface* newSurface(const SkImageInfo&) SK_OVERRIDE;
 
     SkBitmap    fBitmap;
 
     typedef SkBaseDevice INHERITED;
 };
 
 #endif // SkBitmapDevice_DEFINED