add LocalMatrixImageFilter

include/core/SkImageFilter.h

Index: include/core/SkImageFilter.h
diff --git a/include/core/SkImageFilter.h b/include/core/SkImageFilter.h
index 0595010c6fba0321262feca28b887ce3bf272649..398d3224b159adf865835424d3cbd31b8efc2ba9 100644
--- a/include/core/SkImageFilter.h
+++ b/include/core/SkImageFilter.h
@@ -227,7 +227,13 @@ public:
     virtual void computeFastBounds(const SkRect&, SkRect*) const;
 
     // Can this filter DAG compute the resulting bounds of an object-space rectangle?
-    bool canComputeFastBounds() const;
+    virtual bool canComputeFastBounds() const;
+
+    /**
+     *  If this filter can be represented by another filter + a localMatrix, return that filter,
+     *  else return null.
+     */
+    virtual SkImageFilter* newWithLocalMatrix(const SkMatrix& localMatrix) const;
 
     /**
      * Create an SkMatrixImageFilter, which transforms its input by the given matrix.
@@ -345,8 +351,8 @@ protected:
      *  context's clipBounds, and returns the result in "bounds". If there is
      *  no intersection, returns false and leaves "bounds" unchanged.
      */
-    bool applyCropRect(const Context&, const SkBitmap& src, const SkIPoint& srcOffset,
-                       SkIRect* bounds) const;
+    virtual bool applyCropRect(const Context&, const SkBitmap& src, const SkIPoint& srcOffset,
+                               SkIRect* bounds) const;
 
     /** Same as the above call, except that if the resulting crop rect is not
      *  entirely contained by the source bitmap's bounds, it creates a new
@@ -356,8 +362,8 @@ protected:
      *  be used by filters which are not capable of processing a smaller
      *  source bitmap into a larger destination.
      */
-    bool applyCropRect(const Context&, Proxy* proxy, const SkBitmap& src, SkIPoint* srcOffset,
-                       SkIRect* bounds, SkBitmap* result) const;
+    virtual bool applyCropRect(const Context&, Proxy* proxy, const SkBitmap& src,
+                               SkIPoint* srcOffset, SkIRect* bounds, SkBitmap* result) const;
 
     /**
      *  Returns true if the filter can be expressed a single-pass
@@ -385,11 +391,13 @@ protected:
      */
     virtual bool affectsTransparentBlack() const;
 
+    virtual bool usesSrcInput() const { return fUsesSrcInput; }
+
 private:
     friend class SkGraphics;
-    static void PurgeCache();
+    friend class SkLocalMatrixImageFilter;
 
-    bool usesSrcInput() const { return fUsesSrcInput; }
+    static void PurgeCache();
 
     typedef SkFlattenable INHERITED;
     int fInputCount;