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..34c50744042dabac9c7782cd9f74a8e2938dc822 100644
--- a/components/arc/arc_bridge_bootstrap.cc
+++ b/components/arc/arc_bridge_bootstrap.cc
@@ -34,6 +34,8 @@ namespace arc {
 
 namespace {
 
+scoped_ptr<ArcBridgeBootstrap> fake_bootstrap_;

[bartfab (slow), 2016/03/02 14:45:40]

1) Nit: It may not be a fake - it could be a mock. A name like
"bootstrap_for_testing" would be more general.
2) Nit: Globals are prefixed with "g_"
3) Nit: Remove the "_" suffix. This is not a member.
4) This is probably introducing a static initializer, which is not allowed in
Chrome code.

[Polina Bondarenko, 2016/03/06 20:22:33]

Done, fixed to pointer.

+
 // 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 +343,22 @@ void ArcBridgeBootstrapImpl::SetState(State state) {
 }  // namespace
 
 ArcBridgeBootstrap::ArcBridgeBootstrap() {}
-ArcBridgeBootstrap::~ArcBridgeBootstrap() {}
+ArcBridgeBootstrap::~ArcBridgeBootstrap() {

[bartfab (slow), 2016/03/02 14:45:40]

Nit: Add a blank line above.

[Polina Bondarenko, 2016/03/06 20:22:33]

Done.

+  fake_bootstrap_.reset();

[bartfab (slow), 2016/03/02 14:45:40]

This should not be necessary. The global fake_bootstrap_ will eventually be
destroyed, reaping any ArcBridgeBootstrap it may be holding.

+}
 
 // static
 scoped_ptr<ArcBridgeBootstrap> ArcBridgeBootstrap::Create() {
-  return make_scoped_ptr(new ArcBridgeBootstrapImpl());
+  if (fake_bootstrap_ != NULL) {

[bartfab (slow), 2016/03/02 14:45:40]

Nit: s/NULL/nullptr/ or, even easier, "if (fake_bootstrap_) {"

[Polina Bondarenko, 2016/03/06 20:22:33]

Done.

+    return make_scoped_ptr(fake_bootstrap_.release());
+  } else {
+    return make_scoped_ptr(new ArcBridgeBootstrapImpl());
+  }
+}
+
+// static
+void ArcBridgeBootstrap::SetBootstrapForTesting(ArcBridgeBootstrap* bootstrap) {
+  fake_bootstrap_.reset(bootstrap);
 }
 
 }  // namespace arc