Extract ArcTermsOfServiceNegotiator implementation.

chrome/browser/chromeos/arc/optin/arc_optin_preference_handler.cc

Index: chrome/browser/chromeos/arc/optin/arc_optin_preference_handler.cc
diff --git a/chrome/browser/chromeos/arc/optin/arc_optin_preference_handler.cc b/chrome/browser/chromeos/arc/optin/arc_optin_preference_handler.cc
index 4eac145eab7c99a54c428a5afc3fcdb8c4066aed..11972d688fd39a34511fb8db97483b2f1af2b97e 100644
--- a/chrome/browser/chromeos/arc/optin/arc_optin_preference_handler.cc
+++ b/chrome/browser/chromeos/arc/optin/arc_optin_preference_handler.cc
@@ -24,12 +24,13 @@ ArcOptInPreferenceHandler::ArcOptInPreferenceHandler(
 }
 
 void ArcOptInPreferenceHandler::Start() {
-  DCHECK(g_browser_process->local_state());
-  pref_local_change_registrar_.Init(g_browser_process->local_state());
-  pref_local_change_registrar_.Add(
-      metrics::prefs::kMetricsReportingEnabled,
-      base::Bind(&ArcOptInPreferenceHandler::OnMetricsPreferenceChanged,
-                 base::Unretained(this)));
+  if (g_browser_process->local_state()) {

[hidehiko, 2016/11/28 12:42:54]

Unfortunately, injecting ScopedTestingLocalState does not help to test for our
specific case. Specifically, ChangeMetricsReportingState below crashes even with
test objects. So, relaxed for testing, too.

[Luis Héctor Chávez, 2016/11/29 00:15:28]

nit:

if (!g_browser_process->local_state()) {
  // is there a way to log when we're not testing?
  return;
}

[hidehiko, 2016/11/29 17:43:28]

We still want to initialize pref_change_registrar_ below even in test.
Also, there seems no good way to see if this is testing or not...

An alternative is to have another abstraction layer here to inject Fake/Stub,
but IMHO it looks overkill. WDYT?

+    pref_local_change_registrar_.Init(g_browser_process->local_state());
+    pref_local_change_registrar_.Add(
+        metrics::prefs::kMetricsReportingEnabled,
+        base::Bind(&ArcOptInPreferenceHandler::OnMetricsPreferenceChanged,
+                   base::Unretained(this)));
+  }
 
   pref_change_registrar_.Init(pref_service_);
   pref_change_registrar_.Add(
@@ -63,9 +64,11 @@ void ArcOptInPreferenceHandler::OnLocationServicePreferenceChanged() {
 }
 
 void ArcOptInPreferenceHandler::SendMetricsMode() {
-  observer_->OnMetricsModeChanged(
-      ChromeMetricsServiceAccessor::IsMetricsAndCrashReportingEnabled(),
-      IsMetricsReportingPolicyManaged());
+  if (g_browser_process->local_state()) {
+    observer_->OnMetricsModeChanged(
+        ChromeMetricsServiceAccessor::IsMetricsAndCrashReportingEnabled(),
+        IsMetricsReportingPolicyManaged());
+  }
 }
 
 void ArcOptInPreferenceHandler::SendBackupAndRestoreMode() {
@@ -81,7 +84,8 @@ void ArcOptInPreferenceHandler::SendLocationServicesMode() {
 }
 
 void ArcOptInPreferenceHandler::EnableMetrics(bool is_enabled) {
-  ChangeMetricsReportingState(is_enabled);
+  if (g_browser_process->local_state())
+    ChangeMetricsReportingState(is_enabled);
 }
 
 void ArcOptInPreferenceHandler::EnableBackupRestore(bool is_enabled) {