Add ArcEnabled policy implementation

components/arc/arc_bridge_bootstrap.cc

Index: components/arc/arc_bridge_bootstrap.cc
diff --git a/components/arc/arc_bridge_bootstrap.cc b/components/arc/arc_bridge_bootstrap.cc
index 1d7a94f55178b590325f95b1ce23fff6f1c2afb5..309dde087961b7ce08961bc853fa46c4c9c53502 100644
--- a/components/arc/arc_bridge_bootstrap.cc
+++ b/components/arc/arc_bridge_bootstrap.cc
@@ -34,6 +34,8 @@ namespace arc {
 
 namespace {
 
+ArcBridgeBootstrap* g_bootstrap_for_testing = nullptr;
+
 // We do not know the PID of ARC, since Chrome does not create it directly.
 // Since Mojo in POSIX does not use the child PID except as an unique
 // identifier for the routing table, rather than doing a lot of plumbing in the
@@ -341,11 +343,31 @@ void ArcBridgeBootstrapImpl::SetState(State state) {
 }  // namespace
 
 ArcBridgeBootstrap::ArcBridgeBootstrap() {}
-ArcBridgeBootstrap::~ArcBridgeBootstrap() {}
+
+ArcBridgeBootstrap::~ArcBridgeBootstrap() {
+  if (g_bootstrap_for_testing) {
+    delete g_bootstrap_for_testing;
+  }
+}
 
 // static
 scoped_ptr<ArcBridgeBootstrap> ArcBridgeBootstrap::Create() {
-  return make_scoped_ptr(new ArcBridgeBootstrapImpl());
+  if (g_bootstrap_for_testing) {
+    ArcBridgeBootstrap* const result = g_bootstrap_for_testing;
+    g_bootstrap_for_testing = nullptr;
+    return make_scoped_ptr(result);
+  } else {
+    return make_scoped_ptr(new ArcBridgeBootstrapImpl());
+  }
+}
+
+// static
+void ArcBridgeBootstrap::SetBootstrapForTesting(
+    scoped_ptr<ArcBridgeBootstrap> bootstrap) {
+  if (g_bootstrap_for_testing) {
+    delete g_bootstrap_for_testing;
+  }
+  g_bootstrap_for_testing = bootstrap.release();
 }
 
 }  // namespace arc