Replace GrClip with SkClipStack

http://codereview.appspot.com/6449070/



git-svn-id: http://skia.googlecode.com/svn/trunk@4865 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/gpu/SkGpuDevice.h b/include/gpu/SkGpuDevice.h
index f576ae4..539372a 100644
--- a/include/gpu/SkGpuDevice.h
+++ b/include/gpu/SkGpuDevice.h
@@ -130,10 +130,7 @@
 
     GrSkDrawProcs*  fDrawProcs;
 
-    // the clip stack - on loan to us from SkCanvas so it can be NULL.
-    const SkClipStack*  fClipStack;
-    GrClip              fGrClip;
-    GrClipData          fClipData;
+    GrClipData      fClipData;
 
     // state for our offscreen render-target
     TexCache            fCache;