arc: Notify ARC instance failures via callbacks.

components/arc/arc_bridge_service.h

Index: components/arc/arc_bridge_service.h
diff --git a/components/arc/arc_bridge_service.h b/components/arc/arc_bridge_service.h
index 3d719694314ee0219463b873144255e23136cbde..b6b9322348f6d8285488062f1986feab95edcee2 100644
--- a/components/arc/arc_bridge_service.h
+++ b/components/arc/arc_bridge_service.h
@@ -21,8 +21,6 @@ class CommandLine;
 
 namespace arc {
 
-class ArcBridgeBootstrap;
-
 // The Chrome-side service that handles ARC instances and ARC bridge creation.
 // This service handles the lifetime of ARC instances and sets up the
 // communication channel (the ARC bridge) used to send and receive messages.
@@ -63,14 +61,32 @@ class ArcBridgeService : public mojom::ArcBridgeHost {
     STOPPING,
   };
 
+  // Describes the reason the bridge is stopped.
+  enum class StopReason {
+    // ARC instance has been gracefully shut down.
+    SHUTDOWN,
+
+    // Errors occurred during the ARC instance boot. This includes any failures
+    // before the instance is actually attempted to be started, and also
+    // failures on bootstrapping IPC channels with Android.
+    GENERIC_BOOT_FAILURE,
+
+    // ARC instance has crashed.
+    CRASH,
+  };
+
   // Notifies life cycle events of ArcBridgeService.
   class Observer {
    public:
     // Called whenever the state of the bridge has changed.
     // TODO(lchavez): Rename to OnStateChangedForTest
     virtual void OnStateChanged(State state) {}
+
+    // Called whenever the bridge is ready.
     virtual void OnBridgeReady() {}
-    virtual void OnBridgeStopped() {}
+
+    // Called whenever the bridge is stopped.
+    virtual void OnBridgeStopped(StopReason reason) {}
 
     // Called whenever ARC's availability has changed for this system.
     virtual void OnAvailableChanged(bool available) {}
@@ -298,6 +314,11 @@ class ArcBridgeService : public mojom::ArcBridgeHost {
   // Changes the current availability and notifies all observers.
   void SetAvailable(bool availability);
 
+  // Sets the reason the bridge is stopped. This function must be always called
+  // before SetState(State::STOPPED) to report a correct reason with
+  // Observer::OnBridgeStopped().
+  void SetStopReason(StopReason stop_reason);
+
   base::ObserverList<Observer>& observer_list() { return observer_list_; }
 
   bool CalledOnValidThread();
@@ -311,6 +332,7 @@ class ArcBridgeService : public mojom::ArcBridgeHost {
   FRIEND_TEST_ALL_PREFIXES(ArcBridgeTest, Prerequisites);
   FRIEND_TEST_ALL_PREFIXES(ArcBridgeTest, ShutdownMidStartup);
   FRIEND_TEST_ALL_PREFIXES(ArcBridgeTest, Restart);
+  FRIEND_TEST_ALL_PREFIXES(ArcBridgeTest, OnBridgeStopped);
 
   // Called when one of the individual channels is closed.
   void CloseAppChannel();
@@ -411,6 +433,9 @@ class ArcBridgeService : public mojom::ArcBridgeHost {
   // The current state of the bridge.
   ArcBridgeService::State state_;
 
+  // The reason the bridge is stopped.
+  StopReason stop_reason_;
+
   // WeakPtrFactory to use callbacks.
   base::WeakPtrFactory<ArcBridgeService> weak_factory_;