cc: Use CHROMIUM_copy_image for one-copy tile updates.

cc/raster/staging_buffer_pool.h

Index: cc/raster/staging_buffer_pool.h
diff --git a/cc/raster/staging_buffer_pool.h b/cc/raster/staging_buffer_pool.h
index 7ac3ef1af01a33c55091d00655b35535108d00b1..a1536d7b89e322c848558abf51a5a13cda875428 100644
--- a/cc/raster/staging_buffer_pool.h
+++ b/cc/raster/staging_buffer_pool.h
@@ -21,6 +21,10 @@
 #include "cc/output/context_provider.h"
 #include "cc/resources/resource_provider.h"
 
+namespace gfx {
+class GpuFence;
+}
+
 namespace gpu {
 namespace gles2 {
 class GLES2Interface;
@@ -44,10 +48,10 @@ struct StagingBuffer {
   const gfx::Size size;
   const ResourceFormat format;
   std::unique_ptr<gfx::GpuMemoryBuffer> gpu_memory_buffer;
+  std::unique_ptr<gfx::GpuFence> gpu_fence;
   base::TimeTicks last_usage;
-  unsigned texture_id;
   unsigned image_id;
-  unsigned query_id;
+  unsigned fence_id;
   uint64_t content_id;
 };