Add specialized content key class for resources.

src/gpu/GrPath.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 GrPath_DEFINED
 #define GrPath_DEFINED
 
 #include "GrGpuResource.h"
 #include "SkPath.h"
 #include "SkRect.h"
 #include "SkStrokeRec.h"
 
 class GrPath : public GrGpuResource {
 public:
     SK_DECLARE_INST_COUNT(GrPath);
 
     /**
      * Initialize to a path with a fixed stroke. Stroke must not be hairline.
      */
     GrPath(GrGpu* gpu, const SkPath& skPath, const SkStrokeRec& stroke)
         : INHERITED(gpu, kCached_LifeCycle),
           fSkPath(skPath),
           fStroke(stroke),
           fBounds(skPath.getBounds()) {
     }
 
-    static GrResourceKey ComputeKey(const SkPath& path, const SkStrokeRec& stroke);
+    static void ComputeKey(const SkPath& path, const SkStrokeRec& stroke, GrContentKey* key);
     static uint64_t ComputeStrokeKey(const SkStrokeRec&);
 
     bool isEqualTo(const SkPath& path, const SkStrokeRec& stroke) {
         return fSkPath == path && fStroke == stroke;
     }
 
     const SkRect& getBounds() const { return fBounds; }
 
     const SkStrokeRec& getStroke() const { return fStroke; }
 
 protected:
     SkPath fSkPath;
     SkStrokeRec fStroke;
     SkRect fBounds;
 
 private:
     typedef GrGpuResource INHERITED;
 };
 
 #endif