Refactored cacheID in preparation for clip mask caching changes

http://codereview.appspot.com/6458089/



git-svn-id: http://skia.googlecode.com/svn/trunk@5002 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrClipMaskManager.cpp b/src/gpu/GrClipMaskManager.cpp
index 0abe862..a424b02 100644
--- a/src/gpu/GrClipMaskManager.cpp
+++ b/src/gpu/GrClipMaskManager.cpp
@@ -16,6 +16,9 @@
 #include "GrAAConvexPathRenderer.h"
 #include "GrAAHairLinePathRenderer.h"
 #include "GrSWMaskHelper.h"
+#include "GrCacheID.h"
+
+GR_DEFINE_RESOURCE_CACHE_DOMAIN(GrClipMaskManager, GetAlphaMaskDomain)
 
 //#define GR_AA_CLIP 1
 //#define GR_SW_CLIP 1