Force Account Consistency off for Logout call on iOS.

The GaiaAuthFetcher Logout call needs Account Consistency to be
disabled to work properly. On iOS, the state of Account Consistency is
handled by cookies set on the various Google domains. Sadly, the cookie
clearing request is not synchronized with the Logout call and there is
a race between the two.

This CL forces the cookie to be invalid during the Logout request to
ensure the accounts will be cleared. The cookie will eventually be
invalidated in the WKWebView cookie jar when AccountConsistencyService
finishes.

BUG=569501

Review URL: https://codereview.chromium.org/1522873002

Cr-Commit-Position: refs/heads/master@{#365248}

google_apis/gaia/gaia_auth_fetcher.cc

@@ -195,6 +195,10 @@ void GaiaAuthFetcher::SetPendingFetch(bool pending_fetch) {
   fetch_pending_ = pending_fetch;
 }
 
+void GaiaAuthFetcher::SetLogoutHeaders(const std::string& headers) {
+  logout_headers_ = headers;
+}
+
 void GaiaAuthFetcher::CancelRequest() {
   fetcher_.reset();
   fetch_pending_ = false;
@@ -629,7 +633,7 @@ void GaiaAuthFetcher::StartListAccounts() {
 void GaiaAuthFetcher::StartLogOut() {
   DCHECK(!fetch_pending_) << "Tried to fetch two things at once!";
 
-  CreateAndStartGaiaFetcher(std::string(), std::string(), logout_gurl_,
+  CreateAndStartGaiaFetcher(std::string(), logout_headers_, logout_gurl_,
                             net::LOAD_NORMAL);
 }
 

google_apis/gaia/gaia_auth_fetcher.h

@@ -228,6 +228,9 @@ class GaiaAuthFetcher : public net::URLFetcherDelegate {
 
   void SetPendingFetch(bool pending_fetch);
 
+  // Set the headers to use during the Logout call.
+  void SetLogoutHeaders(const std::string& headers);
+
  private:
   // The format of the POST body for IssueAuthToken.
   static const char kIssueAuthTokenFormat[];
@@ -430,6 +433,9 @@ class GaiaAuthFetcher : public net::URLFetcherDelegate {
   std::string requested_service_;
   bool fetch_pending_;
 
+  // Headers used during the Logout call.
+  std::string logout_headers_;
+
   friend class GaiaAuthFetcherTest;
   FRIEND_TEST_ALL_PREFIXES(GaiaAuthFetcherTest, CaptchaParse);
   FRIEND_TEST_ALL_PREFIXES(GaiaAuthFetcherTest, AccountDeletedError);

ios/chrome/browser/signin/gaia_auth_fetcher_ios.mm

@@ -320,7 +320,12 @@ - (void)webView:(WKWebView*)webView
                                        web::BrowserState* browser_state)
     : GaiaAuthFetcher(consumer, source, getter),
       bridge_(new GaiaAuthFetcherIOSBridge(this, browser_state)),
-      browser_state_(browser_state) {}
+      browser_state_(browser_state) {
+  // Account Consistency needs to be disabled for the Logout call. There is a
+  // race with the cookie clearing request (handled by
+  // AccountConsistencyService), so we invalidate the cookie for the call.
+  SetLogoutHeaders("Cookie: X-CHROME-CONNECTED=EXPIRED;");
+}
 
 GaiaAuthFetcherIOS::~GaiaAuthFetcherIOS() {
 }