Make session restore forced tab load delay Finch configurable, and separate first tab loads from su…

chrome/browser/sessions/tab_loader.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_SESSIONS_TAB_LOADER_H_
 #define CHROME_BROWSER_SESSIONS_TAB_LOADER_H_
 
 #include <list>
 #include <set>
 
@@ skipping 50 matching lines @@
   explicit TabLoader(base::TimeTicks restore_started);
   ~TabLoader() override;
 
   // This is invoked once by RestoreTabs to start loading.
   void StartLoading(const std::vector<RestoredTab>& tabs);
 
   // Loads the next tab. If there are no more tabs to load this deletes itself,
   // otherwise |force_load_timer_| is restarted.
   void LoadNextTab();
 
-  // Starts a timer to load load the next tab once expired before the current
-  // tab loading is finished.
+  // Starts |force_load_timer_| to load the first non-visible tab if the timer
+  // expires before a visible tab has finished loading. This uses the same
+  // timer but a different timeout value than StartTimer.
+  void StartFirstTimer();
+
+  // Starts |force_load_timer_| to load the next tab if the timer expires
+  // before the current tab loading is finished. This uses the same timer but a
+  // different timeout value than StartFirstTimer.
   void StartTimer();
 
   // Removes the listeners from the specified tab and removes the tab from
   // the set of tabs to load and list of tabs we're waiting to get a load
   // from.
   void RemoveTab(content::NavigationController* controller);
 
   // Invoked from |force_load_timer_|. Doubles |force_load_delay_multiplier_|
   // and invokes |LoadNextTab| to load the next tab
   void ForceLoadTimerFired();
@@ skipping 42 matching lines @@
   // For keeping TabLoader alive while it's loading even if no
   // SessionRestoreImpls reference it.
   scoped_refptr<TabLoader> this_retainer_;
 
   static TabLoader* shared_tab_loader_;
 
   DISALLOW_COPY_AND_ASSIGN(TabLoader);
 };
 
 #endif  // CHROME_BROWSER_SESSIONS_TAB_LOADER_H_