Add optional sw generated path coverage mask caching

src/gpu/GrSoftwarePathRenderer.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 GrSoftwarePathRenderer_DEFINED
 #define GrSoftwarePathRenderer_DEFINED
 
 #include "GrPathRenderer.h"
 
 class GrTextureProvider;
 
 /**
  * This class uses the software side to render a path to an SkBitmap and
  * then uploads the result to the gpu
  */
 class GrSoftwarePathRenderer : public GrPathRenderer {
 public:
-    GrSoftwarePathRenderer(GrTextureProvider* texProvider) : fTexProvider(texProvider) { }
+    GrSoftwarePathRenderer(GrTextureProvider* texProvider, bool allowCaching)
+            : fTexProvider(texProvider)
+            , fAllowCaching(allowCaching) {}
 private:
     static void DrawNonAARect(GrDrawContext* drawContext,
                               const GrPaint& paint,
                               const GrUserStencilSettings& userStencilSettings,
                               const GrClip& clip,
                               const SkMatrix& viewMatrix,
                               const SkRect& rect,
                               const SkMatrix& localMatrix);
     static void DrawAroundInvPath(GrDrawContext* drawContext,
                                   const GrPaint& paint,
                                   const GrUserStencilSettings& userStencilSettings,
                                   const GrClip& clip,
                                   const SkMatrix& viewMatrix,
                                   const SkIRect& devClipBounds,
                                   const SkIRect& devPathBounds);
 
     StencilSupport onGetStencilSupport(const GrShape&) const override {
         return GrPathRenderer::kNoSupport_StencilSupport;
     }
 
     bool onCanDrawPath(const CanDrawPathArgs&) const override;
 
     bool onDrawPath(const DrawPathArgs&) override;
 
 private:
     GrTextureProvider*     fTexProvider;
+    bool                   fAllowCaching;
 
     typedef GrPathRenderer INHERITED;
 };
 
 #endif