Move SkMatrixImageFilter into core, and add a factory fn for it.

src/core/SkImageFilter.cpp

Index: src/core/SkImageFilter.cpp
diff --git a/src/core/SkImageFilter.cpp b/src/core/SkImageFilter.cpp
index f1553e2ed1c68921e2912d1ab4f30e92423eaf9a..fd98911ca58c705e01c11803976d66b403979d01 100644
--- a/src/core/SkImageFilter.cpp
+++ b/src/core/SkImageFilter.cpp
@@ -11,6 +11,7 @@
 #include "SkChecksum.h"
 #include "SkDevice.h"
 #include "SkLazyPtr.h"
+#include "SkMatrixImageFilter.h"
 #include "SkReadBuffer.h"
 #include "SkWriteBuffer.h"
 #include "SkRect.h"
@@ -368,6 +369,12 @@ bool SkImageFilter::asFragmentProcessor(GrFragmentProcessor**, GrTexture*, const
     return false;
 }
 
+SkImageFilter* SkImageFilter::CreateMatrixFilter(const SkMatrix& matrix,
+                                                 SkFilterQuality filterQuality,
+                                                 SkImageFilter* input) {
+    return SkMatrixImageFilter::Create(matrix, filterQuality, input);
+}
+
 #if SK_SUPPORT_GPU
 
 void SkImageFilter::WrapTexture(GrTexture* texture, int width, int height, SkBitmap* result) {