Implement support for expanding crop rects in image filters

include/core/SkImageFilter.h

Index: include/core/SkImageFilter.h
diff --git a/include/core/SkImageFilter.h b/include/core/SkImageFilter.h
index 4f33f54b6d03a83542811ed1382d2f43a6a2c04d..0f52b69b84ba458772ad816c105f3953df6f8397 100644
--- a/include/core/SkImageFilter.h
+++ b/include/core/SkImageFilter.h
@@ -223,10 +223,25 @@ protected:
     // no inputs.
     virtual bool onFilterBounds(const SkIRect&, const SkMatrix&, SkIRect*) const;
 
-    // Applies "matrix" to the crop rect, and sets "rect" to the intersection of
-    // "rect" and the transformed crop rect. If there is no overlap, returns
-    // false and leaves "rect" unchanged.
-    bool applyCropRect(SkIRect* rect, const SkMatrix& matrix) const;
+    /** Computes source bounds as the src bitmap bounds offset by srcOffset.
+     *  Apply the transformed crop rect to the bounds if any of the
+     *  corresponding edge flags are set. Intersects the result against the
+     *  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;
+
+    /** 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
+     *  bitmap in "result" and pads the edges with transparent black. In that
+     *  case, the srcOffset is modified to be the same as the bounds, since no
+     *  further adjustment is needed by the caller. This version should only
+     *  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;
 
     /**
      *  Returns true if the filter can be expressed a single-pass