ozone: Add sync flag for atomic commit

ui/ozone/platform/drm/gpu/drm_device.cc

 // Copyright 2014 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 "ui/ozone/platform/drm/gpu/drm_device.h"
 
 #include <fcntl.h>
 #include <sys/mman.h>
 #include <unistd.h>
 #include <xf86drm.h>
@@ skipping 470 matching lines @@
 bool DrmDevice::CloseBufferHandle(uint32_t handle) {
   struct drm_gem_close close_request;
   memset(&close_request, 0, sizeof(close_request));
   close_request.handle = handle;
   return !drmIoctl(file_.GetPlatformFile(), DRM_IOCTL_GEM_CLOSE,
                    &close_request);
 }
 
 bool DrmDevice::CommitProperties(drmModePropertySet* properties,
                                  uint32_t flags,
+                                 bool is_sync,
                                  const PageFlipCallback& callback) {
 #if defined(USE_DRM_ATOMIC)
+  flags |= DRM_MODE_PAGE_FLIP_EVENT;
+  if (!is_sync)
+    flags |= DRM_MODE_PAGE_FLIP_ASYNC;
   scoped_ptr<PageFlipPayload> payload(
       new PageFlipPayload(base::ThreadTaskRunnerHandle::Get(), callback));
   if (!drmModePropertySetCommit(file_.GetPlatformFile(), flags, payload.get(),
                                 properties)) {
     // If successful the payload will be removed by the event
     ignore_result(payload.release());
+
+    // If the flip was requested synchronous or if no watcher has been installed
+    // yet, then synchronously handle the page flip events.
+    if (is_sync || !watcher_) {
+      TRACE_EVENT1("drm", "OnDrmEvent", "socket", file_.GetPlatformFile());
+
+      drmEventContext event;
+      event.version = DRM_EVENT_CONTEXT_VERSION;
+      event.page_flip_handler = HandlePageFlipEventOnUI;
+      event.vblank_handler = nullptr;
+
+      drmHandleEvent(file_.GetPlatformFile(), &event);
+    }
     return true;
   }
   return false;
 #else
   return false;
 #endif  // defined(USE_DRM_ATOMIC)
 }
 
 bool DrmDevice::SetMaster() {
   DCHECK(file_.IsValid());
   return (drmSetMaster(file_.GetPlatformFile()) == 0);
 }
 
 bool DrmDevice::DropMaster() {
   DCHECK(file_.IsValid());
   return (drmDropMaster(file_.GetPlatformFile()) == 0);
 }
 
 }  // namespace ui