exo: Implement zcr_linux_explicit_synchronization_v1

components/exo/display.cc

Index: components/exo/display.cc
diff --git a/components/exo/display.cc b/components/exo/display.cc
index df470b28122ce118cf389e2f6aa29f09d28e9c3c..6633944d5d33e0cc8b36016bc76b3e1b97d04259 100644
--- a/components/exo/display.cc
+++ b/components/exo/display.cc
@@ -101,6 +101,20 @@ std::unique_ptr<Buffer> Display::CreateLinuxDMABufBuffer(
       // COMMANDS_COMPLETED queries are required by native pixmaps.
       GL_COMMANDS_COMPLETED_CHROMIUM, use_zero_copy, is_overlay_candidate);
 }
+
+std::unique_ptr<gfx::GpuFence> Display::CreateLinuxFence(base::ScopedFD& fd) {
+  gfx::GpuFenceHandle handle;

[reveman, 2016/10/12 19:20:19]

nit: Please add "TRACE_EVENT1("exo", "Display::CreateLinuxFence", "fd",
fd.get())" followed by a blank line here. These top-level trace events are very
useful for debugging purposes.

FYI, you can launch chrome with --trace-to-console=exo to have tracing output
for exo clients spewed to the console

+
+  handle.fd.fd = fd.get();
+
+  std::unique_ptr<gfx::GpuFence> gpu_fence =
+      aura::Env::GetInstance()
+          ->context_factory()
+          ->GetGpuMemoryBufferManager()
+          ->CreateGpuFenceFromHandle(handle);
+
+  return std::move(gpu_fence);
+}
 #endif
 
 std::unique_ptr<ShellSurface> Display::CreateShellSurface(Surface* surface) {