Add ArcEnabled policy implementation

components/arc/arc_bridge_bootstrap.h

 // 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.
 
 #ifndef COMPONENTS_ARC_ARC_BRIDGE_BOOTSTRAP_H_
 #define COMPONENTS_ARC_ARC_BRIDGE_BOOTSTRAP_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/sequenced_task_runner.h"
@@ skipping 22 matching lines @@
   void set_delegate(Delegate* delegate) { delegate_ = delegate; }
 
   // Starts and bootstraps a connection with the instance. The Delegate's
   // OnConnectionEstablished() will be called if the bootstrapping is
   // successful, or OnStopped() if it is not.
   virtual void Start() = 0;
 
   // Stops the currently-running instance.
   virtual void Stop() = 0;
 
+  // Set instance for testing. ArcBridgeBootstrap owns |bootstrap|
+  // until Create() is called, then passes ownership to the caller.
+  static void SetBootstrapForTesting(
+      scoped_ptr<ArcBridgeBootstrap> bootstrap);
  protected:
   ArcBridgeBootstrap();
 
   // Owned by the caller.
   Delegate* delegate_ = nullptr;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ArcBridgeBootstrap);
 };
 
 }  // namespace arc
 
 #endif  // COMPONENTS_ARC_ARC_BRIDGE_BOOTSTRAP_H_