ozone: choose a card useful for display rather than by default

ui/ozone/platform/dri/dri_wrapper.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/dri/dri_wrapper.h"
 
 #include <fcntl.h>
 #include <sys/mman.h>
 #include <unistd.h>
 #include <xf86drm.h>
@@ skipping 140 matching lines @@
 
 DriWrapper::~DriWrapper() {
   if (fd_ >= 0)
     close(fd_);
 
   if (watcher_)
     watcher_->Shutdown();
 }
 
 void DriWrapper::Initialize() {
-  fd_ = open(device_path_, O_RDWR | O_CLOEXEC);
+  if (device_path_ == NULL)
+    fd_ = OpenFirstDisplayCard();
+  else
+    fd_ = open(device_path_, O_RDWR | O_CLOEXEC);
   if (fd_ < 0)
     PLOG(FATAL) << "open: " << device_path_;
   if (!plane_manager_->Initialize(this))
     LOG(ERROR) << "Failed to initialize the plane manager";
 }
 
 void DriWrapper::InitializeTaskRunner(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner) {
   DCHECK(!task_runner_);
   task_runner_ = task_runner;
@@ skipping 236 matching lines @@
   DCHECK(fd_ >= 0);
   return (drmSetMaster(fd_) == 0);
 }
 
 bool DriWrapper::DropMaster() {
   DCHECK(fd_ >= 0);
   return (drmDropMaster(fd_) == 0);
 }
 
 }  // namespace ui