Add fence support for TransferBuffers

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 287 matching lines @@
      * @param height           height of rectangle to write in pixels.
      * @param config           the pixel config of the source buffer
      * @param transferBuffer   GrBuffer to read pixels from (type must be "kCpuToGpu")
      * @param offset           offset from the start of the buffer
      * @param rowBytes         number of bytes between consecutive rows. Zero
      *                         means rows are tightly packed.
      */
     bool transferPixels(GrSurface* surface,
                         int left, int top, int width, int height,
                         GrPixelConfig config, GrBuffer* transferBuffer,
-                        size_t offset, size_t rowBytes);
+                        size_t offset, size_t rowBytes, GrFence* fence);
 
     /**
      * This is can be called before allocating a texture to be a dst for copySurface. This is only
      * used for doing dst copies needed in blends, thus the src is always a GrRenderTarget. It will
      * populate the origin, config, and flags fields of the desc such that copySurface can
      * efficiently succeed.
      */
     virtual bool initDescForDstCopy(const GrRenderTarget* src, GrSurfaceDesc* desc) const = 0;
 
     // After the client interacts directly with the 3D context state the GrGpu
@@ skipping 45 matching lines @@
     // directly to the Gpu object.
     virtual GrGpuCommandBuffer* createCommandBuffer(
             GrRenderTarget* target,
             const GrGpuCommandBuffer::LoadAndStoreInfo& colorInfo,
             const GrGpuCommandBuffer::LoadAndStoreInfo& stencilInfo) = 0;
 
     // Called by drawtarget when flushing.
     // Provides a hook for post-flush actions (e.g. PLS reset and Vulkan command buffer submits).
     virtual void finishDrawTarget() {}
 
+    virtual GrFence SK_WARN_UNUSED_RESULT insertFence() const = 0;
+    virtual bool waitFence(GrFence, uint64_t timeout = 1000) const = 0;
+    virtual void deleteFence(GrFence) const = 0;
+
     ///////////////////////////////////////////////////////////////////////////
     // Debugging and Stats
 
     class Stats {
     public:
 #if GR_GPU_STATS
         Stats() { this->reset(); }
 
         void reset() {
             fRenderTargetBinds = 0;
@@ skipping 214 matching lines @@
     SkSTArray<1, MultisampleSpecs, true>   fMultisampleSpecs;
     // 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