adding uniqueID to GrContext

include/gpu/GrContext.h

 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrContext_DEFINED
 #define GrContext_DEFINED
 
@@ skipping 496 matching lines @@
      * surface or using it as a texture.
      */
     void prepareSurfaceForExternalRead(GrSurface*);
 
     /**
      * Provides a perfomance hint that the render target's contents are allowed
      * to become undefined.
      */
     void discardRenderTarget(GrRenderTarget*);
 
+    /**
+     * An ID associated with this context, guaranteed to be unique.
+     */
+    uint32_t uniqueID() { return fUniqueID; }
+
     ///////////////////////////////////////////////////////////////////////////
     // Legacy functions, to be removed once Chromium stops using them.
 
     enum ScratchTexMatch {
         kExact_ScratchTexMatch = GrTextureProvider::kExact_ScratchTexMatch,
         kApprox_ScratchTexMatch = GrTextureProvider::kApprox_ScratchTexMatch
     };
 
     GrTexture* refScratchTexture(const GrSurfaceDesc& desc, ScratchTexMatch match) {
         return this->textureProvider()->refScratchTexture(
@@ skipping 80 matching lines @@
     struct CleanUpData {
         PFCleanUpFunc fFunc;
         void*         fInfo;
     };
 
     SkTDArray<CleanUpData>          fCleanUpData;
 
     int                             fMaxTextureSizeOverride;
 
     const Options                   fOptions;
+    const uint32_t                  fUniqueID;
 
     GrContext(const Options&); // init must be called after the constructor.
     bool init(GrBackend, GrBackendContext);
     void initMockContext();
     void initCommon();
 
     void setupDrawBuffer();
 
     class AutoCheckFlush;
     // Sets the paint and returns the target to draw into.
@@ skipping 48 matching lines @@
      */
     static void TextBlobCacheOverBudgetCB(void* data);
 
     // TODO see note on createTextContext
     friend class SkGpuDevice;
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif