Mac: Don't update prefs file unnecessarily when activating windows.

chrome/browser/ui/cocoa/browser_window_controller.mm

 // 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.
 
 #import "chrome/browser/ui/cocoa/browser_window_controller.h"
 
 #include <cmath>
 #include <numeric>
 
 #include "base/command_line.h"
@@ skipping 37 matching lines @@
 #import "chrome/browser/ui/cocoa/browser_window_utils.h"
 #import "chrome/browser/ui/cocoa/dev_tools_controller.h"
 #import "chrome/browser/ui/cocoa/download/download_shelf_controller.h"
 #include "chrome/browser/ui/cocoa/extensions/extension_keybinding_registry_cocoa.h"
 #import "chrome/browser/ui/cocoa/fast_resize_view.h"
 #import "chrome/browser/ui/cocoa/find_bar/find_bar_bridge.h"
 #import "chrome/browser/ui/cocoa/find_bar/find_bar_cocoa_controller.h"
 #import "chrome/browser/ui/cocoa/framed_browser_window.h"
 #import "chrome/browser/ui/cocoa/fullscreen_window.h"
 #import "chrome/browser/ui/cocoa/infobars/infobar_container_controller.h"
+#include "chrome/browser/ui/cocoa/last_active_browser_cocoa.h"
 #import "chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_editor.h"
 #import "chrome/browser/ui/cocoa/presentation_mode_controller.h"
 #import "chrome/browser/ui/cocoa/profiles/avatar_base_controller.h"
 #import "chrome/browser/ui/cocoa/profiles/avatar_button_controller.h"
 #import "chrome/browser/ui/cocoa/profiles/avatar_icon_controller.h"
 #import "chrome/browser/ui/cocoa/status_bubble_mac.h"
 #import "chrome/browser/ui/cocoa/tab_contents/overlayable_contents_controller.h"
 #import "chrome/browser/ui/cocoa/tab_contents/sad_tab_controller.h"
 #import "chrome/browser/ui/cocoa/tab_contents/tab_contents_controller.h"
 #import "chrome/browser/ui/cocoa/tabs/tab_strip_controller.h"
@@ skipping 515 matching lines @@
     [[self window] orderOut:self];
     return NO;
   }
 
   // the tab strip is empty, it's ok to close the window
   return YES;
 }
 
 // Called right after our window became the main window.
 - (void)windowDidBecomeMain:(NSNotification*)notification {
-  BrowserList::SetLastActive(browser_.get());
-  [self saveWindowPositionIfNeeded];
+  if (chrome::GetLastActiveBrowser() != browser_) {
+    BrowserList::SetLastActive(browser_.get());
+    [self saveWindowPositionIfNeeded];
+  }
 
   [[[self window] contentView] cr_recursivelyInvokeBlock:^(id view) {
       if ([view conformsToProtocol:@protocol(ThemedWindowDrawing)])
         [view windowDidChangeActive];
   }];
 
   extensions::ExtensionCommandsGlobalRegistry::Get(browser_->profile())
       ->set_registry_for_active_window(extension_keybinding_registry_.get());
 }
 
@@ skipping 1614 matching lines @@
 
 - (BOOL)supportsBookmarkBar {
   return [self supportsWindowFeature:Browser::FEATURE_BOOKMARKBAR];
 }
 
 - (BOOL)isTabbedWindow {
   return browser_->is_type_tabbed();
 }
 
 @end  // @implementation BrowserWindowController(WindowType)