Fix incorrect window show state after session restore.

chrome/browser/sessions/session_restore.cc

 // Copyright 2012 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.
 
 #include "chrome/browser/sessions/session_restore.h"
 
 #include <algorithm>
 #include <list>
 #include <set>
 #include <string>
@@ skipping 364 matching lines @@
 
     // After the for loop this contains the last TABBED_BROWSER. Is null if no
     // tabbed browsers exist.
     Browser* last_browser = nullptr;
     bool has_tabbed_browser = false;
 
     // After the for loop, this contains the browser to activate, if one of the
     // windows has the same id as specified in active_window_id.
     Browser* browser_to_activate = nullptr;
 
-    // Determine if there is a visible window.
+    // Determine if there is a visible window, or if the active window exists.
+    // Even if all windows are ui::SHOW_STATE_MINIMIZED, if one of them is the
+    // active window it will be made visible by the call to
+    // browser_to_activate->window()->Activate() later on in this method.
     bool has_visible_browser = false;
     for (std::vector<sessions::SessionWindow*>::iterator i = windows->begin();
          i != windows->end(); ++i) {
-      if ((*i)->show_state != ui::SHOW_STATE_MINIMIZED)
+      if ((*i)->show_state != ui::SHOW_STATE_MINIMIZED ||
+          (*i)->window_id.id() == active_window_id)

[sky, 2015/09/28 14:54:05]

How is that the active window is in a minimized state?

[shrike, 2015/09/28 17:53:41]

As browser windows become active, SessionService::OnBrowserSetLastActive() gets
called from BrowserList::SetLastActive(). However if you minimize the last
visible browser window, SessionService::OnBrowserSetLastActive() does not get
called, so session restore is stuck remembering the last active browser window.

To clear out the last active browser window
SessionService::OnBrowserSetLastActive() would have to be called with either a
dummy browser window object or a nullptr. It looks like a nullptr can't be
passed in because SessionService::OnBrowserSet() immediately calls
SessionService::ShouldTrackBrowser() and it looks like that method would crash
if it received a nullptr.

[sky, 2015/09/28 19:04:01]

Ok, makes sense.

         has_visible_browser = true;
     }
 
     for (std::vector<sessions::SessionWindow*>::iterator i = windows->begin();
          i != windows->end(); ++i) {
       Browser* browser = nullptr;
       if (!has_tabbed_browser &&
           (*i)->type == sessions::SessionWindow::TYPE_TABBED)
         has_tabbed_browser = true;
       if (i == windows->begin() &&
@@ skipping 458 matching lines @@
   if (prioritize_tabs == "mru")
     return SMART_RESTORE_MODE_MRU;
   if (prioritize_tabs == "simple")
     return SMART_RESTORE_MODE_SIMPLE;
   return SMART_RESTORE_MODE_OFF;
 }
 
 // static
 base::CallbackList<void(int)>*
     SessionRestore::on_session_restored_callbacks_ = nullptr;