[ARC] Add browser test of ArcAuthService

chrome/browser/chromeos/arc/arc_auth_context.cc

Index: chrome/browser/chromeos/arc/arc_auth_context.cc
diff --git a/chrome/browser/chromeos/arc/arc_auth_context.cc b/chrome/browser/chromeos/arc/arc_auth_context.cc
index 99d78b3e6723b584ed0d6a8b4920df17935194b2..b8d6a0dfca1e11e6eb27f0554d220a435c1bd2e6 100644
--- a/chrome/browser/chromeos/arc/arc_auth_context.cc
+++ b/chrome/browser/chromeos/arc/arc_auth_context.cc
@@ -29,7 +29,8 @@ constexpr base::TimeDelta kRefreshTokenTimeout =
 
 }  // namespace
 
-ArcAuthContext::ArcAuthContext(Profile* profile) {
+ArcAuthContext::ArcAuthContext(Profile* profile)
+    : skip_merge_session_for_testing_(false) {
   // Reuse storage used in ARC OptIn platform app.
   const std::string site_url = base::StringPrintf(
       "%s://%s/persist?%s", content::kGuestScheme, ArcSupportHost::kHostAppId,
@@ -94,6 +95,12 @@ void ArcAuthContext::OnRefreshTokenTimeout() {
 void ArcAuthContext::StartFetchers() {
   DCHECK(!refresh_token_timeout_.IsRunning());
   ResetFetchers();
+
+  if (skip_merge_session_for_testing_) {
+    OnMergeSessionSuccess("");
+    return;
+  }
+
   ubertoken_fetcher_.reset(
       new UbertokenFetcher(token_service_, this, GaiaConstants::kChromeOSSource,
                            storage_partition_->GetURLRequestContext()));