Get OffsetImageFilter really working with SkSpecialImages

include/core/SkImageFilter.h

Index: include/core/SkImageFilter.h
diff --git a/include/core/SkImageFilter.h b/include/core/SkImageFilter.h
index 29f6f7b760e2b2e27f9ab2dad92d9d8e0e2b5034..be36b90499a224c66001f0c6c9903d48eb2a3dc0 100644
--- a/include/core/SkImageFilter.h
+++ b/include/core/SkImageFilter.h
@@ -23,6 +23,7 @@ class SkBaseDevice;
 class SkBitmap;
 class SkColorFilter;
 struct SkIPoint;
+class SkSpecialImage;
 
 /**
  *  Base class for image filters. If one is installed in the paint, then
@@ -42,7 +43,10 @@ public:
         static Cache* Create(size_t maxBytes);
         static Cache* Get();
         virtual bool get(const Key& key, SkBitmap* result, SkIPoint* offset) const = 0;
+        virtual SkSpecialImage* get(const Key& key, SkIPoint* offset) const = 0;
         virtual void set(const Key& key, const SkBitmap& result, const SkIPoint& offset) = 0;
+        virtual void set(const Key& key, SkSpecialImage* image, const SkIPoint& offset) = 0;
+
         virtual void purge() {}
         virtual void purgeByKeys(const Key[], int) {}
     };
@@ -148,6 +152,8 @@ public:
     bool filterImageDeprecated(Proxy*, const SkBitmap& src, const Context&,
                                SkBitmap* result, SkIPoint* offset) const;
 
+    SkSpecialImage* filterImage(SkSpecialImage* src, const Context&, SkIPoint* offset) const;
+
     enum MapDirection {
         kForward_MapDirection,
         kReverse_MapDirection
@@ -260,6 +266,11 @@ public:
                                              SkFilterQuality,
                                              SkImageFilter* input = NULL);
 
+    SkSpecialImage* filterInput(int index,
+                                SkSpecialImage* src,
+                                const Context&, 
+                                SkIPoint* offset) const;
+
 #if SK_SUPPORT_GPU
     // Helper function which invokes GPU filter processing on the
     // input at the specified "index". If the input is null, it leaves
@@ -345,6 +356,15 @@ protected:
     virtual bool onFilterImageDeprecated(Proxy*, const SkBitmap& src, const Context&,
                                          SkBitmap* result, SkIPoint* offset) const;
 
+    // TODO: remove this when all the image filters are converted
+    virtual bool supportsUnifiedFiltering() const { return false; }
+
+    virtual SkSpecialImage* onFilterImage(SkSpecialImage* src, const Context&,
+                                          SkIPoint* offset) const {
+        return nullptr;
+    }
+
+
     /**
      * This function recurses into its inputs with the given clip rect (first
      * argument), calls filterBounds() with the given map direction on each,
@@ -414,6 +434,9 @@ protected:
     bool applyCropRectDeprecated(const Context&, Proxy* proxy, const SkBitmap& src,
                                  SkIPoint* srcOffset, SkIRect* bounds, SkBitmap* result) const;
 
+    SkSpecialImage* applyCropRect(const Context&, SkSpecialImage* src, SkIPoint* srcOffset,
+                                  SkIRect* bounds) const;
+
     /**
      *  Returns true if the filter can be expressed a single-pass
      *  GrProcessor, used to process this filter on the GPU, or false if