Image filters: de-nest SkImageFilter::Cache and Cache::Key.

include/core/SkDevice.h

Index: include/core/SkDevice.h
diff --git a/include/core/SkDevice.h b/include/core/SkDevice.h
index 5301d1e3ffca189f285228f1ec3331510a662f7c..73c35c33419f0934797ae7994ab1732b4c35558a 100644
--- a/include/core/SkDevice.h
+++ b/include/core/SkDevice.h
@@ -11,13 +11,13 @@
 #include "SkRefCnt.h"
 #include "SkCanvas.h"
 #include "SkColor.h"
-#include "SkImageFilter.h"
 #include "SkSurfaceProps.h"
 
 class SkBitmap;
 class SkClipStack;
 class SkDraw;
 class SkDrawFilter;
+class SkImageFilterCache;
 struct SkIRect;
 class SkMatrix;
 class SkMetaData;
@@ -394,7 +394,7 @@ private:
      */
     virtual void flush() {}
 
-    virtual SkImageFilter::Cache* getImageFilterCache() { return NULL; }
+    virtual SkImageFilterCache* getImageFilterCache() { return NULL; }
 
     SkIPoint    fOrigin;
     SkMetaData* fMetaData;