arc-bridge: Move most methods to Mojo interfaces

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.
+
+module arc;
+
+// Enumerates the types of wake lock the ARC instance can request from the
+// host.
+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
+};
+
+interface PowerHost {
+  // Acquire and release wake locks on the host side.
+  OnAcquireDisplayWakeLock(DisplayWakeLockType type);
+  OnReleaseDisplayWakeLock(DisplayWakeLockType type);
+};
+
+interface PowerInstance {
+  // Establishes full-duplex communication with the host.
+  Init(PowerHost host_ptr);
+};