ozone: gbm: Fail earlier if device can't be opened

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 12 matching lines @@
 namespace ui {
 
 // Wraps DRM calls into a nice interface. Used to provide different
 // implementations of the DRM calls. For the actual implementation the DRM API
 // would be called. In unit tests this interface would be stubbed.
 class DriWrapper {
  public:
   DriWrapper(const char* device_path);
   virtual ~DriWrapper();
 
+  // Open device.
+  virtual void Initialize();
+
   // 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);
 
   // Used to configure CRTC with ID |crtc_id| to use the connector in
   // |connectors|. The CRTC will be configured with mode |mode| and will display
   // the framebuffer with ID |framebuffer|. Before being able to display the
   // framebuffer, it should be registered with the CRTC using |AddFramebuffer|.
   virtual bool SetCrtc(uint32_t crtc_id,
@@ skipping 85 matching lines @@
                                  void* pixels);
 
   int get_fd() const { return fd_; }
 
  protected:
   // The file descriptor associated with this wrapper. All DRM operations will
   // be performed using this FD.
   int fd_;
 
  private:
+  // Path to DRM device.
+  const char* device_path_;
+
   DISALLOW_COPY_AND_ASSIGN(DriWrapper);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRI_DRI_WRAPPER_H_