Fetch policy with refresh token.

chrome/browser/chromeos/policy/policy_oauth2_token_fetcher.h

Index: chrome/browser/chromeos/policy/policy_oauth2_token_fetcher.h
diff --git a/chrome/browser/chromeos/policy/policy_oauth2_token_fetcher.h b/chrome/browser/chromeos/policy/policy_oauth2_token_fetcher.h
index af2671afc0090a0bbc314baef88e46b66cca4ba5..61829485df3b372d20621ae1252c721886814204 100644
--- a/chrome/browser/chromeos/policy/policy_oauth2_token_fetcher.h
+++ b/chrome/browser/chromeos/policy/policy_oauth2_token_fetcher.h
@@ -53,6 +53,10 @@ class PolicyOAuth2TokenFetcher
   // Starts process of minting device management service OAuth2 access token.
   void Start();
 
+  // Starts minting device management service OAuth2 access token with the given
+  // |oauth2_refresh_token|.
+  void StartWithRefreshToken(const std::string& oauth2_refresh_token);

[Mattias Nissler (ping if slow), 2015/04/28 06:50:43]

Please turn this into a 3rd constructor for consistency.

[achuithb, 2015/04/28 18:20:08]

I considered this. The first problem is that the type of auth_code and
refresh_token is the same (const std::string&), so the ctor signatures would be
the same. The bigger issue is that multiple ctors are just a variation of
function overloading which is not recommended stylistically. 

I think the way to go is to have one ctor, and have methods
StartWithBrowserContext, StartWithAuthCode, and StartWithRefreshToken. I'll do
this in a follow-up cleanup CL to avoid clutter in this CL. 

Hope that's ok.

[Mattias Nissler (ping if slow), 2015/04/29 07:10:52]

That's a good point.
I don't agree with this. The style guide allows overloads where they make sense.
Having different constructors that initialize the class differently seems
totally fine here. Having a single Start() function also makes it clearer what
the calling code is supposed to do, whereas multiple StartWithXYZ functions may
create the misunderstanding that they could / should be called in order.
Please do. Happy to review the CL.

+
   // Returns true if we have previously attempted to fetch tokens with this
   // class and failed.
   bool failed() const {
@@ -110,10 +114,10 @@ class PolicyOAuth2TokenFetcher
   std::string oauth2_access_token_;
 
   // The retry counter. Increment this only when failure happened.
-  int retry_count_;
+  int retry_count_ = 0;
 
   // True if we have already failed to fetch the policy.
-  bool failed_;
+  bool failed_ = false;
 
   // The callback to invoke when done.
   TokenCallback callback_;