tunnel down texture-size-constraint to imagefilters

include/core/SkImageFilter.h

Index: include/core/SkImageFilter.h
diff --git a/include/core/SkImageFilter.h b/include/core/SkImageFilter.h
index 64e1581373d0c6eeb0a3b9e2ed1e4ee4d0d991ea..0c3d4c2ddf4f66a2081591edd42f8b535807236d 100644
--- a/include/core/SkImageFilter.h
+++ b/include/core/SkImageFilter.h
@@ -44,18 +44,31 @@ public:
         virtual void purge() {}
     };
 
+    enum SizeConstraint {
+        kExact_SizeConstraint,
+        kApprox_SizeConstraint,
+    };
+
     class Context {
     public:
-        Context(const SkMatrix& ctm, const SkIRect& clipBounds, Cache* cache) :
-            fCTM(ctm), fClipBounds(clipBounds), fCache(cache) {
-        }
+        Context(const SkMatrix& ctm, const SkIRect& clipBounds, Cache* cache,
+                SizeConstraint constraint)
+            : fCTM(ctm)
+            , fClipBounds(clipBounds)
+            , fCache(cache)
+            , fSizeConstraint(constraint)
+        {}
+
         const SkMatrix& ctm() const { return fCTM; }
         const SkIRect& clipBounds() const { return fClipBounds; }
         Cache* cache() const { return fCache; }
+        SizeConstraint sizeConstraint() const { return fSizeConstraint; }
+
     private:
-        SkMatrix fCTM;
-        SkIRect  fClipBounds;
-        Cache*   fCache;
+        SkMatrix        fCTM;
+        SkIRect         fClipBounds;
+        Cache*          fCache;
+        SizeConstraint  fSizeConstraint;
     };
 
     class CropRect {
@@ -255,7 +268,7 @@ public:
     // Otherwise, the filter will be processed in software and
     // uploaded to the GPU.
     bool filterInputGPU(int index, SkImageFilter::Proxy* proxy, const SkBitmap& src, const Context&,
-                        SkBitmap* result, SkIPoint* offset) const;
+                        SkBitmap* result, SkIPoint* offset, bool relaxSizeConstraint = true) const;
 #endif
 
     SK_TO_STRING_PUREVIRT()
@@ -345,7 +358,7 @@ protected:
     // calls filterImage() on that input, and returns true on success.
     // i.e., return !getInput(index) || getInput(index)->filterImage(...);
     bool filterInput(int index, Proxy*, const SkBitmap& src, const Context&,
-                     SkBitmap* result, SkIPoint* offset) const;
+                     SkBitmap* result, SkIPoint* offset, bool relaxSizeConstraint = true) const;
 
     /**
      *  Return true (and return a ref'd colorfilter) if this node in the DAG is just a