Add specialized content key class for resources.

src/gpu/GrTexturePriv.h

Index: src/gpu/GrTexturePriv.h
diff --git a/src/gpu/GrTexturePriv.h b/src/gpu/GrTexturePriv.h
index c093a9bbc63d7d45e95790f73ddf3ec4345afb85..8add4e1c495e563a5ca922825bd6cd241858013f 100644
--- a/src/gpu/GrTexturePriv.h
+++ b/src/gpu/GrTexturePriv.h
@@ -39,14 +39,7 @@ public:
         return GrTexture::kNotAllocated_MipMapsStatus != fTexture->fMipMapsStatus;
     }
 
-    static GrResourceKey ComputeKey(const GrGpu* gpu,
-                                    const GrTextureParams* params,
-                                    const GrSurfaceDesc& desc,
-                                    const GrCacheID& cacheID);
     static void ComputeScratchKey(const GrSurfaceDesc&, GrScratchKey*);
-    static bool NeedsResizing(const GrResourceKey& key);
-    static bool NeedsBilerp(const GrResourceKey& key);
-
 
     // TODO: Move this logic and the shift values out of here and to the callers.
     SkFixed normalizeFixedX(SkFixed x) const {