Adding ArcBridge interface for synchronizing brightness settings

components/arc/common/power.mojom

 // Copyright 2015 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.
 
-// Next min version: 3
+// Next min version: 4
 
 module arc.mojom;
 
 // Enumerates the types of wake lock the ARC instance can request from the
 // host.
 [Extensible]
 enum DisplayWakeLockType {
   // Does not allow the screen to dim, turn off, or lock; prevents
   // idle suspend.
   BRIGHT = 0,
 
   // Allows dimming the screen, but prevents it from turning off or locking.
   // Also prevents idle suspend.
   DIM = 1
 };
 
-// Next method ID: 3
+// Next method ID: 4
 interface PowerHost {
   // Acquire and release wake locks on the host side.
   OnAcquireDisplayWakeLock@0(DisplayWakeLockType type);
   OnReleaseDisplayWakeLock@1(DisplayWakeLockType type);
 
   // Checks if there is a display on.
   [MinVersion=1] IsDisplayOn@2() => (bool is_on);
+
+  // Request that the screen brightness be changed to |percent|.
+  // |percent| is of the range [0, 100]
+  [MinVersion=3] OnScreenBrightnessUpdateRequest@3(double percent);
 };
 
-// Next method ID: 4
+// Next method ID: 5
 interface PowerInstance {
   // Establishes full-duplex communication with the host.
   Init@0(PowerHost host_ptr);
 
   // Alerts the instance to a change in interactive state.
   [MinVersion=1] SetInteractive@1(bool enabled);
 
   // Called when the system is about to suspend. The callback will be invoked
   // when pre-suspend work is complete.
   [MinVersion=2] Suspend@2() => ();
 
   // Called when the system has just resumed.
   [MinVersion=2] Resume@3();
+
+  // Update Android brightness settings.
+  // |percent| is of the range [0, 100]
+  [MinVersion=3] UpdateScreenBrightnessSettings@4(double percent);
 };