Reland of Simplify SkGpuBlurUtils::GaussianBlur method

src/effects/SkGpuBlurUtils.h

Index: src/effects/SkGpuBlurUtils.h
diff --git a/src/effects/SkGpuBlurUtils.h b/src/effects/SkGpuBlurUtils.h
index 7dbfa138ea4a27c3a05362bbab9a9cdc2020fa60..8bc4377f5980af690cf3efd364450c2f7cf63b37 100644
--- a/src/effects/SkGpuBlurUtils.h
+++ b/src/effects/SkGpuBlurUtils.h
@@ -24,8 +24,6 @@
     * Applies a 2D Gaussian blur to a given texture.
     * @param context         The GPU context
     * @param srcTexture      The source texture to be blurred.
-    * @param canClobberSrc   If true, srcTexture may be overwritten, and
-    *                        may be returned as the result.
     * @param gammaCorrect    Should blur be gamma-correct (sRGB to linear, etc...)
     * @param dstBounds       The destination bounds, relative to the source texture.
     * @param srcBounds       The source bounds, relative to the source texture. If non-null,
@@ -37,7 +35,6 @@
     */
     GrTexture* GaussianBlur(GrContext* context,
                             GrTexture* srcTexture,
-                            bool canClobberSrc,
                             bool gammaCorrect,
                             const SkRect& dstBounds,
                             const SkRect* srcBounds,