Don't call purgeCache() from within GrResource memebers.

src/gpu/GrGpu.h

Index: src/gpu/GrGpu.h
diff --git a/src/gpu/GrGpu.h b/src/gpu/GrGpu.h
index 656761bd326029582352e0c91963644c7dcd7e9a..8e16db0ac97047f3632fdd5481051918591a29e3 100644
--- a/src/gpu/GrGpu.h
+++ b/src/gpu/GrGpu.h
@@ -523,6 +523,8 @@ private:
     // these are mutable so they can be created on-demand
     mutable GrIndexBuffer*                                              fQuadIndexBuffer;
     bool                                                                fContextIsDirty;
+    // Used to abandon/release all resources created by this GrGpu. TODO: Move this 
+    // functionality to GrResourceCache.
     ResourceList                                                        fResourceList;
 
     typedef GrDrawTarget INHERITED;