cc: Move GpuMemoryBuffer allocation to worker threads.

cc/resources/zero_copy_raster_worker_pool.cc

Index: cc/resources/zero_copy_raster_worker_pool.cc
diff --git a/cc/resources/zero_copy_raster_worker_pool.cc b/cc/resources/zero_copy_raster_worker_pool.cc
index 1e920903bc26804422ab94c9554ef4765bd4b6a4..b5b4d5f4966c820b23b532dfbf05fb7b28be51ef 100644
--- a/cc/resources/zero_copy_raster_worker_pool.cc
+++ b/cc/resources/zero_copy_raster_worker_pool.cc
@@ -24,35 +24,36 @@ class RasterBufferImpl : public RasterBuffer {
                    const Resource* resource)
       : lock_(resource_provider, resource->id()),
         resource_(resource),
-        buffer_(NULL) {}
+        gpu_memory_buffer_(nullptr),
+        buffer_(nullptr) {}
 
   // Overridden from RasterBuffer:
   virtual skia::RefPtr<SkCanvas> AcquireSkCanvas() override {
-    gfx::GpuMemoryBuffer* gpu_memory_buffer = lock_.gpu_memory_buffer();
-    if (!gpu_memory_buffer)
+    gpu_memory_buffer_ = lock_.GetGpuMemoryBuffer();
+    if (!gpu_memory_buffer_)
       return skia::AdoptRef(SkCreateNullCanvas());
 
-    buffer_ = gpu_memory_buffer->Map();
+    buffer_ = gpu_memory_buffer_->Map();
     RasterWorkerPool::AcquireBitmapForBuffer(&bitmap_,
                                              buffer_,
                                              resource_->format(),
                                              resource_->size(),
-                                             gpu_memory_buffer->GetStride());
+                                             gpu_memory_buffer_->GetStride());
     return skia::AdoptRef(new SkCanvas(bitmap_));
   }
   virtual void ReleaseSkCanvas(const skia::RefPtr<SkCanvas>& canvas) override {
-    gfx::GpuMemoryBuffer* gpu_memory_buffer = lock_.gpu_memory_buffer();
-    if (!gpu_memory_buffer)
+    if (!gpu_memory_buffer_)
       return;
 
     RasterWorkerPool::ReleaseBitmapForBuffer(
         &bitmap_, buffer_, resource_->format());
-    gpu_memory_buffer->Unmap();
+    gpu_memory_buffer_->Unmap();
   }
 
  private:
   ResourceProvider::ScopedWriteLockGpuMemoryBuffer lock_;
   const Resource* resource_;
+  gfx::GpuMemoryBuffer* gpu_memory_buffer_;
   void* buffer_;
   SkBitmap bitmap_;