gpu: Add GpuFence framework.

gpu/ipc/client/gpu_channel_host.h

Index: gpu/ipc/client/gpu_channel_host.h
diff --git a/gpu/ipc/client/gpu_channel_host.h b/gpu/ipc/client/gpu_channel_host.h
index 5acf6c79a5fdbcf4d917dd6967b2e9b1336f789e..b394d755d522569a215704c29ffa7ed54d7094a6 100644
--- a/gpu/ipc/client/gpu_channel_host.h
+++ b/gpu/ipc/client/gpu_channel_host.h
@@ -27,6 +27,7 @@
 #include "ipc/message_filter.h"
 #include "ipc/message_router.h"
 #include "ui/events/latency_info.h"
+#include "ui/gfx/gpu_fence.h"
 #include "ui/gfx/gpu_memory_buffer.h"
 
 namespace base {
@@ -154,6 +155,15 @@ class GPU_EXPORT GpuChannelHost
   // Reserve one unused image ID.
   int32_t ReserveImageId();
 
+  // Returns a GPU fence handle to the fence that can be sent via
+  // IPC to the GPU process. The caller is responsible for ensuring it is
+  // closed. Returns an invalid handle on failure.
+  gfx::GpuFenceHandle ShareGpuFenceToGpuProcess(
+      const gfx::GpuFenceHandle& source_handle);
+
+  // Reserve one unused fence ID.
+  int32_t ReserveFenceId();
+
   // Generate a route ID guaranteed to be unique for this channel.
   int32_t GenerateRouteID();
 
@@ -273,6 +283,9 @@ class GPU_EXPORT GpuChannelHost
   // Image IDs are allocated in sequence.
   base::AtomicSequenceNumber next_image_id_;
 
+  // Fence IDs are allocated in sequence.
+  base::AtomicSequenceNumber next_fence_id_;
+
   // Route IDs are allocated in sequence.
   base::AtomicSequenceNumber next_route_id_;