small fix for clip mask cache clear

src/gpu/GrClipMaskManager.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrClipMaskManager_DEFINED
 #define GrClipMaskManager_DEFINED
 
@@ skipping 62 matching lines @@
      */
     void purgeResources();
 
     bool isClipInStencil() const {
         return kStencil_ClipMaskType == fCurrClipMaskType;
     }
     bool isClipInAlpha() const {
         return kAlpha_ClipMaskType == fCurrClipMaskType;
     }
 
-    void invalidateStencilMask() {
-        if (kStencil_ClipMaskType == fCurrClipMaskType) {
-            fCurrClipMaskType = kNone_ClipMaskType;
-        }
-    }
-
     GrContext* getContext() {
         return fAACache.getContext();
     }
 
     void setClipTarget(GrClipTarget*);
 
     void adjustPathStencilParams(GrStencilSettings*);
 
 private:
     /**
@@ skipping 96 matching lines @@
     } fCurrClipMaskType;
 
     GrClipMaskCache fAACache;       // cache for the AA path
     GrClipTarget*   fClipTarget;
     StencilClipMode fClipMode;
 
     typedef SkNoncopyable INHERITED;
 };
 
 #endif // GrClipMaskManager_DEFINED