Fix image filters for PDF backend.

include/core/SkDevice.h

 /*
  * Copyright 2010 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.
  */
 
 #ifndef SkDevice_DEFINED
 #define SkDevice_DEFINED
 
@@ skipping 103 matching lines @@
         SkASSERT(fAttachedToCanvas);
         this->unlockPixels();
 #ifdef SK_DEBUG
         fAttachedToCanvas = false;
 #endif
     };
 
 protected:
     enum Usage {
        kGeneral_Usage,
-       kSaveLayer_Usage  // <! internal use only
+       kSaveLayer_Usage,  // <! internal use only
+       kImageFilter_Usage // <! internal use only
     };
 
     struct TextFlags {
         uint32_t    fFlags;     // SkPaint::getFlags()
     };
 
     /**
      *  Device may filter the text flags for drawing text here. If it wants to
      *  make a change to the specified values, it should write them into the
      *  textflags parameter (output) and return true. If the paint is fine as
@@ skipping 226 matching lines @@
     // any clip information.
     // TODO: move to SkBitmapDevice
     virtual void replaceBitmapBackendForRasterSurface(const SkBitmap&) {}
 
     virtual bool forceConservativeRasterClip() const { return false; }
 
     // just called by SkCanvas when built as a layer
     void setOrigin(int x, int y) { fOrigin.set(x, y); }
     // just called by SkCanvas for saveLayer
     SkBaseDevice* createCompatibleDeviceForSaveLayer(const SkImageInfo&);
+    // just called by SkCanvas for imagefilter
+    SkBaseDevice* createCompatibleDeviceForImageFilter(const SkImageInfo&);
 
     virtual SkBaseDevice* onCreateDevice(const SkImageInfo&, Usage) {
         return NULL;
     }
 
     /** Causes any deferred drawing to the device to be completed.
      */
     virtual void flush() {}
 
     virtual SkImageFilter::Cache* getImageFilterCache() { return NULL; }
 
     SkIPoint    fOrigin;
     SkMetaData* fMetaData;
     SkDeviceProperties* fLeakyProperties;   // will always exist.
 
 #ifdef SK_DEBUG
     bool        fAttachedToCanvas;
 #endif
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif