exo: Implement zcr_linux_explicit_synchronization_v1

components/exo/display.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/exo/display.h"
 
 #include <iterator>
 #include <utility>
 
 #include "ash/common/shell_window_ids.h"
@@ skipping 83 matching lines @@
                                                gfx::BufferFormat::RGBX_8888};
   bool is_overlay_candidate =
       std::find(std::begin(kOverlayFormats), std::end(kOverlayFormats),
                 format) != std::end(kOverlayFormats);
 
   return base::MakeUnique<Buffer>(
       std::move(gpu_memory_buffer), GL_TEXTURE_EXTERNAL_OES,
       // 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) {
   TRACE_EVENT1("exo", "Display::CreateShellSurface", "surface",
                surface->AsTracedValue());
 
   if (surface->HasSurfaceDelegate()) {
     DLOG(ERROR) << "Surface has already been assigned a role";
     return nullptr;
   }
@@ skipping 77 matching lines @@
       notification_surface_manager_->GetSurface(notification_id)) {
     DLOG(ERROR) << "Invalid notification id, id=" << notification_id;
     return nullptr;
   }
 
   return base::MakeUnique<NotificationSurface>(notification_surface_manager_,
                                                surface, notification_id);
 }
 
 }  // namespace exo