mash: Migrate [Keyboard]Brightness code to ash/common.

ash/accelerators/accelerator_controller.h

Index: ash/accelerators/accelerator_controller.h
diff --git a/ash/accelerators/accelerator_controller.h b/ash/accelerators/accelerator_controller.h
index 2ed610d18b8e0a4d4ce0eb419ac841e6b3e683e4..4953d191752011edf6cba74bbc2450cef406e767 100644
--- a/ash/accelerators/accelerator_controller.h
+++ b/ash/accelerators/accelerator_controller.h
@@ -27,7 +27,6 @@ class AcceleratorManager;
 namespace ash {
 
 struct AcceleratorData;
-class BrightnessControlDelegate;
 class ExitWarningHandler;
 class ImeControlDelegate;
 class KeyboardBrightnessControlDelegate;
@@ -101,15 +100,10 @@ class ASH_EXPORT AcceleratorController : public ui::AcceleratorTarget {
   // Returns the restriction for the current context.
   AcceleratorProcessingRestriction GetCurrentAcceleratorRestriction();
 
-  void SetBrightnessControlDelegate(
-      std::unique_ptr<BrightnessControlDelegate> brightness_control_delegate);
   void SetImeControlDelegate(
       std::unique_ptr<ImeControlDelegate> ime_control_delegate);
   void SetScreenshotDelegate(
       std::unique_ptr<ScreenshotDelegate> screenshot_delegate);
-  BrightnessControlDelegate* brightness_control_delegate() const {
-    return brightness_control_delegate_.get();
-  }
   ScreenshotDelegate* screenshot_delegate() {
     return screenshot_delegate_.get();
   }
@@ -175,9 +169,6 @@ class ASH_EXPORT AcceleratorController : public ui::AcceleratorTarget {
   // A tracker for the current and previous accelerators.
   std::unique_ptr<ui::AcceleratorHistory> accelerator_history_;
 
-  // TODO(derat): BrightnessControlDelegate is also used by the system tray;
-  // move it outside of this class.
-  std::unique_ptr<BrightnessControlDelegate> brightness_control_delegate_;
   std::unique_ptr<ImeControlDelegate> ime_control_delegate_;
   std::unique_ptr<KeyboardBrightnessControlDelegate>
       keyboard_brightness_control_delegate_;

[msw, 2016/07/07 22:41:59]

I could also move this to WmShell for consistency, but it's not necessary nor
clearly better; wdyt?

[James Cook, 2016/07/07 23:08:49]

Yeah, I would move it. It exists for tests and to have someone own
KeyboardBrightnessController. I think it makes sense to keep it with the other
one.

[msw, 2016/07/08 01:40:48]

Done.