Add notification mechanism when BrowserActionButton's icon has been updated.

chrome/browser/ui/views/extensions/browser_action_overflow_menu_controller.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/views/extensions/browser_action_overflow_menu_controller.h"
 
 #include "base/message_loop/message_loop.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/extensions/extension_action.h"
 #include "chrome/browser/extensions/extension_action_manager.h"
 #include "chrome/browser/extensions/extension_context_menu_model.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/views/extensions/browser_action_drag_data.h"
 #include "chrome/browser/ui/views/toolbar/browser_action_view.h"
 #include "chrome/browser/ui/views/toolbar/browser_actions_container.h"
 #include "extensions/common/extension.h"
 #include "ui/gfx/canvas.h"
 #include "ui/views/controls/menu/menu_item_view.h"
 #include "ui/views/controls/menu/menu_runner.h"
 #include "ui/views/controls/menu/submenu_view.h"
 #include "ui/views/widget/widget.h"
 
+// In the browser actions container's chevron menu, a MenuItemView's icon comes
+// from BrowserActionView::GetIconWithBadge() (which comes from
+// BrowserActionButton's icon) when the MenuItemView is created. But,
+// BrowserActionButton's icon may be not yet loaded in time because it is read

[sky, 2014/02/18 16:03:51]

may not be loaded

+// from file system in another thread.
+// The IconUpdater will update the MenuItemView's icon when the
+// BrowserActionButton's icon has been updated.
+class IconUpdater : public BrowserActionButton::IconObserver,
+                    public views::MenuItemView::LifecycleObserver {
+ public:
+  IconUpdater(views::MenuItemView* menu_item_view,
+              BrowserActionButton* button)
+      : menu_item_view_(menu_item_view),
+        button_(button) {
+    DCHECK(menu_item_view);
+    DCHECK(button);
+    button->set_icon_observer(this);
+  }
+  virtual ~IconUpdater() {}
+
+  // Overridden from BrowserActionButton::IconObserver:
+  virtual void OnIconUpdated(const gfx::ImageSkia& icon) OVERRIDE {
+    menu_item_view_->SetIcon(icon);
+  }
+
+  // Overridden from views::MenuItemView::LifecycleObserver:
+  virtual void OnDeleted(views::MenuItemView* view) OVERRIDE {
+    button_->set_icon_observer(NULL);
+    delete this;
+  }
+ private:
+  // The menu item view whose icon might be updated.
+  views::MenuItemView* menu_item_view_;
+
+  // The button to be observed. When its icon was updated, update the
+  // corresponding menu item view's icon.
+  BrowserActionButton* button_;
+
+  DISALLOW_COPY_AND_ASSIGN(IconUpdater);
+};
+
 BrowserActionOverflowMenuController::BrowserActionOverflowMenuController(
     BrowserActionsContainer* owner,
     Browser* browser,
     views::MenuButton* menu_button,
     const std::vector<BrowserActionView*>& views,
     int start_index)
     : owner_(owner),
       browser_(browser),
       observer_(NULL),
       menu_button_(menu_button),
       menu_(NULL),
       views_(&views),
       start_index_(start_index),
       for_drop_(false) {
   menu_ = new views::MenuItemView(this);
   menu_runner_.reset(new views::MenuRunner(menu_));
   menu_->set_has_icons(true);
 
   size_t command_id = 1;  // Menu id 0 is reserved, start with 1.
   for (size_t i = start_index; i < views_->size(); ++i) {
     BrowserActionView* view = (*views_)[i];
-    menu_->AppendMenuItemWithIcon(
+    views::MenuItemView* menu_item = menu_->AppendMenuItemWithIcon(
         command_id,
         base::UTF8ToUTF16(view->button()->extension()->name()),
         view->GetIconWithBadge());
 
     // Set the tooltip for this item.
     base::string16 tooltip = base::UTF8ToUTF16(
         extensions::ExtensionActionManager::Get(owner_->profile())->
         GetBrowserAction(*view->button()->extension())->
         GetTitle(owner_->GetCurrentTabId()));
     menu_->SetTooltip(tooltip, command_id);
 
+    IconUpdater* icon_updater = new IconUpdater(menu_item, view->button());
+    menu_item->set_lifecycle_observer(icon_updater);
+
     ++command_id;
   }
 }
 
 BrowserActionOverflowMenuController::~BrowserActionOverflowMenuController() {
   if (observer_)
     observer_->NotifyMenuDeleted(this);
 }
 
 bool BrowserActionOverflowMenuController::RunMenu(views::Widget* window,
@@ skipping 152 matching lines @@
 
 BrowserActionView* BrowserActionOverflowMenuController::ViewForId(
     int id, size_t* index) {
   // The index of the view being dragged (GetCommand gives a 1-based index into
   // the overflow menu).
   size_t view_index = owner_->VisibleBrowserActions() + id - 1;
   if (index)
     *index = view_index;
   return owner_->GetBrowserActionViewAt(view_index);
 }