Revert of Use the GrCacheable ID to eliminate the need for notifications to GrGpuGL when textures and RTs are…

include/gpu/GrCacheable.h

Index: include/gpu/GrCacheable.h
diff --git a/include/gpu/GrCacheable.h b/include/gpu/GrCacheable.h
index 5cd9b0d1c43003f9ec4c0cd2c59f094c53b28b55..344ae6b58319edd1e41fe7222ef0087a188c79e3 100644
--- a/include/gpu/GrCacheable.h
+++ b/include/gpu/GrCacheable.h
@@ -46,12 +46,12 @@
      * not change when the content of the GrCacheable object changes. This will never return
      * 0.
      */
-    uint64_t getInstanceID() const { return fInstanceID; }
+    uint32_t getGenerationID() const;
 
 protected:
     GrCacheable()
         : fCacheEntry(NULL)
-        , fInstanceID(CreateInstanceID()) {}
+        , fGenID(0) {}
 
     bool isInCache() const { return NULL != fCacheEntry; }
 
@@ -64,10 +64,8 @@
     void didChangeGpuMemorySize() const;
 
 private:
-    static uint64_t CreateInstanceID();
-
     GrResourceCacheEntry*   fCacheEntry;  // NULL if not in cache
-    mutable uint64_t        fInstanceID;
+    mutable uint32_t        fGenID;
 
     typedef SkRefCnt INHERITED;
 };