Begin instanced rendering for simple shapes

src/gpu/GrGpu.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGpu_DEFINED
 #define GrGpu_DEFINED
 
@@ skipping 20 matching lines @@
 class GrPathRendererChain;
 class GrPathRendering;
 class GrPipeline;
 class GrPrimitiveProcessor;
 class GrRenderTarget;
 class GrStencilAttachment;
 class GrStencilSettings;
 class GrSurface;
 class GrTexture;
 
+namespace gr_instanced { class InstancedRendering; }
+
 class GrGpu : public SkRefCnt {
 public:
     /**
      * Create an instance of GrGpu that matches the specified backend. If the requested backend is
      * not supported (at compile-time or run-time) this returns nullptr. The context will not be
      * fully constructed and should not be used by GrGpu until after this function returns.
      */
     static GrGpu* Create(GrBackend, GrBackendContext, const GrContextOptions&, GrContext* context);
 
     ////////////////////////////////////////////////////////////////////////////
@@ skipping 89 matching lines @@
      * @param intendedType    hint to the graphics subsystem about what the buffer will be used for.
      * @param accessPattern   hint to the graphics subsystem about how the data will be accessed.
      * @param data            optional data with which to initialize the buffer.
      *
      * @return the buffer if successful, otherwise nullptr.
      */
     GrBuffer* createBuffer(size_t size, GrBufferType intendedType, GrAccessPattern accessPattern,
                            const void* data = nullptr);
 
     /**
+     * Creates an instanced rendering object if it is supported on this platform.
+     */
+    virtual gr_instanced::InstancedRendering* createInstancedRenderingIfSupported() {
+        return nullptr;
+    }
+
+    /**
      * Resolves MSAA.
      */
     void resolveRenderTarget(GrRenderTarget* target);
 
     /** Info struct returned by getReadPixelsInfo about performing intermediate draws before
         reading pixels for performance or correctness. */
     struct ReadPixelTempDrawInfo {
         /** If the GrGpu is requesting that the caller do a draw to an intermediate surface then
             this is descriptor for the temp surface. The draw should always be a rect with
             dst 0,0,w,h. */
@@ skipping 412 matching lines @@
     }
 
     ResetTimestamp                                                      fResetTimestamp;
     uint32_t                                                            fResetBits;
     SkTArray<const MultisampleSpecs*, true>                             fMultisampleSpecsMap;
     GrTAllocator<MultisampleSpecs>                                      fMultisampleSpecsAllocator;
     // The context owns us, not vice-versa, so this ptr is not ref'ed by Gpu.
     GrContext*                                                          fContext;
 
     friend class GrPathRendering;
+    friend class gr_instanced::InstancedRendering;
     typedef SkRefCnt INHERITED;
 };
 
 #endif