Make SkGpuBlurUtils::GaussianBlur more drawContext centric

src/effects/SkGpuBlurUtils.h

Index: src/effects/SkGpuBlurUtils.h
diff --git a/src/effects/SkGpuBlurUtils.h b/src/effects/SkGpuBlurUtils.h
index 8bc4377f5980af690cf3efd364450c2f7cf63b37..0d37f158be9c0270dc44efe9a5e50b9e3bed2ecb 100644
--- a/src/effects/SkGpuBlurUtils.h
+++ b/src/effects/SkGpuBlurUtils.h
@@ -9,19 +9,18 @@
 #define SkGpuBlurUtils_DEFINED
 
 #if SK_SUPPORT_GPU
-#include "GrTextureProvider.h"
+#include "GrDrawContext.h"
 
-class GrTexture;
 class GrContext;
-#endif
+class GrTexture;
 
 struct SkRect;
 
 namespace SkGpuBlurUtils {
-
-#if SK_SUPPORT_GPU
   /**
-    * Applies a 2D Gaussian blur to a given texture.
+    * Applies a 2D Gaussian blur to a given texture. The blurred result is returned
+    * as a drawContext in case the caller wishes to future draw into the result.
+    * Note: one of sigmaX and sigmaY should be non-zero!
     * @param context         The GPU context
     * @param srcTexture      The source texture to be blurred.
     * @param gammaCorrect    Should blur be gamma-correct (sRGB to linear, etc...)
@@ -30,18 +29,17 @@ namespace SkGpuBlurUtils {
     *                        no pixels will be sampled outside of this rectangle.
     * @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
-    * new texture.  It is the caller's responsibility to unref this texture.
+    * @return                The drawContext containing the blurred result.
     */
-    GrTexture* GaussianBlur(GrContext* context,
-                            GrTexture* srcTexture,
-                            bool gammaCorrect,
-                            const SkRect& dstBounds,
-                            const SkRect* srcBounds,
-                            float sigmaX,
-                            float sigmaY);
-#endif
+    sk_sp<GrDrawContext> GaussianBlur(GrContext* context,
+                                      GrTexture* srcTexture,
+                                      bool gammaCorrect,
+                                      const SkRect& dstBounds,
+                                      const SkRect* srcBounds,
+                                      float sigmaX,
+                                      float sigmaY);
 
 };
 
 #endif
+#endif