Implement support for a Context parameter in image filters

src/core/SkBitmapDevice.cpp

Index: src/core/SkBitmapDevice.cpp
diff --git a/src/core/SkBitmapDevice.cpp b/src/core/SkBitmapDevice.cpp
index 8524f0b72b4312746d10a307767bda14b6e7acb8..621b76515bb07c6378a30bb3794ee48d9afa073e 100644
--- a/src/core/SkBitmapDevice.cpp
+++ b/src/core/SkBitmapDevice.cpp
@@ -164,7 +164,7 @@ bool SkBitmapDevice::canHandleImageFilter(const SkImageFilter*) {
 }
 
 bool SkBitmapDevice::filterImage(const SkImageFilter* filter, const SkBitmap& src,
-                                 const SkMatrix& ctm, SkBitmap* result,
+                                 const SkImageFilter::Context& ctx, SkBitmap* result,
                                  SkIPoint* offset) {
     return false;
 }