Switch from Delegate to Observer.

components/arc/arc_bridge_service_impl.cc

Index: components/arc/arc_bridge_service_impl.cc
diff --git a/components/arc/arc_bridge_service_impl.cc b/components/arc/arc_bridge_service_impl.cc
index 93f42b183013e461537e5fed81525d28248ca6cf..2c413b99b6470ff59c499c5fa9c6b5c3c7e27777 100644
--- a/components/arc/arc_bridge_service_impl.cc
+++ b/components/arc/arc_bridge_service_impl.cc
@@ -18,7 +18,6 @@
 #include "chromeos/chromeos_switches.h"
 #include "chromeos/dbus/dbus_method_call_status.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
-#include "components/arc/arc_bridge_host_impl.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
 
@@ -39,6 +38,9 @@ ArcBridgeServiceImpl::ArcBridgeServiceImpl()
 }
 
 ArcBridgeServiceImpl::~ArcBridgeServiceImpl() {
+  if (bootstrap_)
+    bootstrap_->RemoveObserver(this);
+
   DCHECK(g_arc_bridge_service == this);
   g_arc_bridge_service = nullptr;
 }
@@ -85,7 +87,7 @@ void ArcBridgeServiceImpl::PrerequisitesChanged() {
 
     SetState(State::CONNECTING);
     bootstrap_ = factory_.Run();

[Luis Héctor Chávez, 2016/10/03 18:05:32]

Should you unregister the previous bootstrap here if it exists? Otherwise
there'll be a DCHECK that its observer list is non-empty. Or is there a
guarantee that OnStopped will definitely be called before? If there is (e.g.
successive Shutdown()/HandleStartup() calls being guarded by ArcAuthService or
something like that), please document it here.

[hidehiko, 2016/10/04 05:34:45]

Added RemoveObserver, which is much safer.

-    bootstrap_->set_delegate(this);
+    bootstrap_->AddObserver(this);
     bootstrap_->Start();
   } else {
     if (session_started_)
@@ -108,22 +110,18 @@ void ArcBridgeServiceImpl::StopInstance() {
   VLOG(1) << "Stopping ARC";
   DCHECK(bootstrap_.get());
   SetState(State::STOPPING);
-  arc_bridge_host_.reset();
 
   // Note: this can call OnStopped() internally as a callback.
   bootstrap_->Stop();
 }
 
-void ArcBridgeServiceImpl::OnConnectionEstablished(
-    mojom::ArcBridgeInstancePtr instance) {
+void ArcBridgeServiceImpl::OnReady() {
   DCHECK(CalledOnValidThread());
   if (state() != State::CONNECTING) {
     VLOG(1) << "StopInstance() called while connecting";
     return;
   }
 
-  arc_bridge_host_.reset(new ArcBridgeHostImpl(std::move(instance)));
-
   // The container can be considered to have been successfully launched, so
   // restart if the connection goes down without being requested.
   reconnect_ = true;
@@ -134,7 +132,7 @@ void ArcBridgeServiceImpl::OnConnectionEstablished(
 void ArcBridgeServiceImpl::OnStopped(StopReason stop_reason) {
   DCHECK(CalledOnValidThread());
   VLOG(0) << "ARC stopped: " << stop_reason;
-  arc_bridge_host_.reset();
+  bootstrap_->RemoveObserver(this);
   bootstrap_.reset();
   SetStopReason(stop_reason);
   SetState(State::STOPPED);