Fix flaky linux panel tests related to active state checks

chrome/browser/ui/panels/base_panel_browser_test.cc

 // Copyright (c) 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/ui/panels/base_panel_browser_test.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop.h"
@@ skipping 310 matching lines @@
     EXPECT_TRUE(panel->auto_resizable());
   }
 
   if (params.show_flag == SHOW_AS_ACTIVE) {
     panel->Show();
   } else {
     panel->ShowInactive();
   }
 
   if (params.wait_for_fully_created) {
-    MessageLoopForUI::current()->RunAllPending();
-
 #if defined(OS_LINUX)
     // On bots, we might have a simple window manager which always activates new
     // windows, and can't always deactivate them. Re-activate the main tabbed
     // browser to "deactivate" the newly created panel.
     if (params.expected_active_state == SHOW_AS_INACTIVE &&
         ui::GuessWindowManager() == ui::WM_ICE_WM) {
+      // Wait for new panel to become active before deactivating to ensure
+      // the activated notification is consumed before we wait for the panel
+      // to become inactive.
+      WaitForPanelActiveState(panel, SHOW_AS_ACTIVE);
       browser()->window()->Activate();
     }
 #endif
     // More waiting, because gaining or losing focus may require inter-process
     // asynchronous communication, and it is not enough to just run the local
     // message loop to make sure this activity has completed.
     WaitForPanelActiveState(panel, params.expected_active_state);
 
     // On Linux, window size is not available right away and we should wait
     // before moving forward with the test.
@@ skipping 120 matching lines @@
 }
 
 void BasePanelBrowserTest::MoveMouse(const gfx::Point& position) {
   PanelManager::GetInstance()->mouse_watcher()->NotifyMouseMovement(position);
 }
 
 std::string BasePanelBrowserTest::MakePanelName(int index) {
   std::string panel_name("Panel");
   return panel_name + base::IntToString(index);
 }