Migrate --enable-arc and --arc-available part 1.

chrome/browser/chromeos/login/session/chrome_session_manager.cc

Index: chrome/browser/chromeos/login/session/chrome_session_manager.cc
diff --git a/chrome/browser/chromeos/login/session/chrome_session_manager.cc b/chrome/browser/chromeos/login/session/chrome_session_manager.cc
index 66cef620218c97466e3c2f964879f17e4b1d9ad9..eb9e8326f336d6b094d84da0c8e54119ddbf3acd 100644
--- a/chrome/browser/chromeos/login/session/chrome_session_manager.cc
+++ b/chrome/browser/chromeos/login/session/chrome_session_manager.cc
@@ -33,7 +33,6 @@
 #include "chromeos/cryptohome/cryptohome_parameters.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/session_manager_client.h"
-#include "components/arc/arc_bridge_service.h"
 #include "components/prefs/pref_service.h"
 #include "components/signin/core/account_id/account_id.h"
 #include "components/signin/core/browser/signin_manager.h"
@@ -106,11 +105,7 @@ void StartRestoreAfterCrashSession(Profile* user_profile,
     user_session_mgr->InitializeCRLSetFetcher(user);
     user_session_mgr->InitializeCertificateTransparencyComponents(user);
 
-    if (arc::ArcBridgeService::GetEnabled(
-            base::CommandLine::ForCurrentProcess())) {
-      arc::ArcServiceLauncher::Get()->OnPrimaryUserProfilePrepared(
-          user_profile);
-    }
+    arc::ArcServiceLauncher::Get()->OnPrimaryUserProfilePrepared(user_profile);

[hidehiko, 2017/01/24 10:57:36]

Note: because ArcServiceLauncher instance is always created regardless of
IsArcAvailable(), we should be able to call this unconditionally.

Note that, in case of that IsArcAvailable() returns false,
ArcSessionManager::OnPrimaryUserProfilePrepared() handles it.

[Luis Héctor Chávez, 2017/01/24 17:00:37]

Please note this in a comment.

Also, I believe the motivation behind the check was to avoid
instantiating/initializing stuff unless it was necessary, so I'd vote to keep it
unless it's causing some complication elsewhere.

[hidehiko, 2017/01/24 18:05:56]

I prefer the consistency, here.
ArcService instances are initialized regardless of the IsArcAvailable(), so I
think it makes sense to call OnPrimaryUserProfilePreapred() as well, where some
services are initialized in the function.

So, the diff in a case IsArcAvailable() returns false then is whether Shutdown()
is called or not, in ArcSessionManager. However, if IsArcAvailable() returns
false, no-one can starts arc so it should be almost no-op. Thus, I do not think
we have much benefit by culling the call.

WDYT?

[Luis Héctor Chávez, 2017/01/26 17:48:26]

I still believe we should try to avoid even instantiating the services when ARC
is not available, but I also buy the consistency argument. Let's fix that in a
separate change.

[hidehiko, 2017/01/30 13:15:18]

Thanks. I created a tracking bug. crbug.com/686703.

 
     // Send the PROFILE_PREPARED notification and call SessionStarted()
     // so that the Launcher and other Profile dependent classes are created.