Accelerate handling of clipRRect in calls to SkPictureUtils::GatherPixelRefs

BUG=https://code.google.com/p/chromium/issues/detail?id=173718
Review URL: https://codereview.appspot.com/7252048

git-svn-id: http://skia.googlecode.com/svn/trunk@7527 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/utils/SkPictureUtils.cpp b/src/utils/SkPictureUtils.cpp
index d8041df..de4b440 100644
--- a/src/utils/SkPictureUtils.cpp
+++ b/src/utils/SkPictureUtils.cpp
@@ -11,6 +11,7 @@
 #include "SkDevice.h"
 #include "SkPixelRef.h"
 #include "SkShader.h"
+#include "SkRRect.h"
 
 class PixelRefSet {
 public:
@@ -181,6 +182,10 @@
                           bool doAA) SK_OVERRIDE {
         return this->INHERITED::clipRect(path.getBounds(), op, false);
     }
+    virtual bool clipRRect(const SkRRect& rrect, SkRegion::Op op,
+                           bool doAA) SK_OVERRIDE {
+        return this->INHERITED::clipRect(rrect.getBounds(), op, false);
+    }
 
 private:
     typedef SkCanvas INHERITED;