[ARC] Add browser test of ArcAuthService

chrome/browser/chromeos/arc/arc_auth_context.h

Index: chrome/browser/chromeos/arc/arc_auth_context.h
diff --git a/chrome/browser/chromeos/arc/arc_auth_context.h b/chrome/browser/chromeos/arc/arc_auth_context.h
index c0aee9cedc78a9d7766de409d19575c78891eeba..a3a7e2a00ba4490ef7b5089643e767a0bf74184e 100644
--- a/chrome/browser/chromeos/arc/arc_auth_context.h
+++ b/chrome/browser/chromeos/arc/arc_auth_context.h
@@ -60,6 +60,10 @@ class ArcAuthContext : public UbertokenConsumer,
   void OnMergeSessionSuccess(const std::string& data) override;
   void OnMergeSessionFailure(const GoogleServiceAuthError& error) override;
 
+  // Skips the merge session, instead calling the callback passed to |Prepare()|
+  // once the refresh token is available. Use only in testing.
+  void SkipMergeSessionForTesting() { skip_merge_session_for_testing_ = true; }
+
  private:
   void OnRefreshTokenTimeout();
 
@@ -71,6 +75,9 @@ class ArcAuthContext : public UbertokenConsumer,
   std::string account_id_;
   std::string full_account_id_;
 
+  // Whether the merge session should be skipped. Set to true only in testing.
+  bool skip_merge_session_for_testing_ = false;
+
   // Owned by content::BrowserContent. Used to isolate cookies for auth server
   // communication and shared with ARC OptIn UI platform app.
   content::StoragePartition* storage_partition_ = nullptr;