chromeos: Turn off displays on suspend

ui/ozone/common/native_display_delegate_ozone.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_COMMON_NATIVE_DISPLAY_DELEGATE_OZONE_H_
 #define UI_OZONE_COMMON_NATIVE_DISPLAY_DELEGATE_OZONE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 12 matching lines @@
   // NativeDisplayDelegate overrides:
   void Initialize() override;
   void GrabServer() override;
   void UngrabServer() override;
   void TakeDisplayControl(const DisplayControlCallback& callback) override;
   void RelinquishDisplayControl(
       const DisplayControlCallback& callback) override;
   void SyncWithServer() override;
   void SetBackgroundColor(uint32_t color_argb) override;
   void ForceDPMSOn() override;
+  void GetCachedDisplays(const GetDisplaysCallback& callback) override;
   void GetDisplays(const GetDisplaysCallback& callback) override;
   void AddMode(const ui::DisplaySnapshot& output,
                const ui::DisplayMode* mode) override;
   void Configure(const ui::DisplaySnapshot& output,
                  const ui::DisplayMode* mode,
                  const gfx::Point& origin,
                  const ConfigureCallback& callback) override;
   void CreateFrameBuffer(const gfx::Size& size) override;
   void GetHDCPState(const ui::DisplaySnapshot& output,
                     const GetHDCPStateCallback& callback) override;
@@ skipping 14 matching lines @@
 
  private:
   std::vector<std::unique_ptr<DisplaySnapshot>> displays_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeDisplayDelegateOzone);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_COMMON_NATIVE_DISPLAY_DELEGATE_OZONE_H_