[Ozone-Dri] Gracefully handle DRM devices with no resources

ui/ozone/platform/dri/dri_wrapper.h

 // 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.
 
 #ifndef UI_OZONE_PLATFORM_DRI_DRI_WRAPPER_H_
 #define UI_OZONE_PLATFORM_DRI_DRI_WRAPPER_H_
 
 #include <stdint.h>
 
 #include <vector>
@@ skipping 30 matching lines @@
 class OZONE_EXPORT DriWrapper : public base::RefCountedThreadSafe<DriWrapper> {
  public:
   typedef base::Callback<void(unsigned int /* frame */,
                               unsigned int /* seconds */,
                               unsigned int /* useconds */)> PageFlipCallback;
 
   DriWrapper(const base::FilePath& device_path);
   DriWrapper(const base::FilePath& device_path, base::File file);
 
   // Open device.
-  virtual void Initialize();
+  virtual bool Initialize();
 
   // |task_runner| will be used to asynchronously page flip.
   virtual void InitializeTaskRunner(
       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner);
 
   // Get the CRTC state. This is generally used to save state before using the
   // CRTC. When the user finishes using the CRTC, the user should restore the
   // CRTC to it's initial state. Use |SetCrtc| to restore the state.
   virtual ScopedDrmCrtcPtr GetCrtc(uint32_t crtc_id);
 
@@ skipping 123 matching lines @@
 
   // Watcher for |fd_| listening for page flip events.
   scoped_refptr<IOWatcher> watcher_;
 
   DISALLOW_COPY_AND_ASSIGN(DriWrapper);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRI_DRI_WRAPPER_H_