Implement crop rect for SkImageFilter

src/effects/SkGpuBlurUtils.h

Index: src/effects/SkGpuBlurUtils.h
diff --git a/src/effects/SkGpuBlurUtils.h b/src/effects/SkGpuBlurUtils.h
index 6769d566703f9b7285b0a99ee8405c7eb0fdeffc..98be8130e28b7d178db781db0d0d896649ddb9cf 100644
--- a/src/effects/SkGpuBlurUtils.h
+++ b/src/effects/SkGpuBlurUtils.h
@@ -25,6 +25,8 @@ namespace SkGpuBlurUtils {
     * @param canClobberSrc   If true, srcTexture may be overwritten, and
     *                        may be returned as the result.
     * @param rect            The destination rectangle.
+    * @param cropToRect      If true, do not sample any pixels outside the
+    *                        source rect.
     * @param sigmaX          The blur's standard deviation in X.
     * @param sigmaY          The blur's standard deviation in Y.
     * @return the blurred texture, which may be srcTexture reffed, or a
@@ -34,6 +36,7 @@ namespace SkGpuBlurUtils {
                             GrTexture* srcTexture,
                             bool canClobberSrc,
                             const SkRect& rect,
+                            bool cropToRect,
                             float sigmaX,
                             float sigmaY);
 #endif