[UI Views] Check menu() in ZoomView

chrome/browser/ui/views/toolbar/app_menu.cc

 // Copyright 2013 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/toolbar/app_menu.h"
 
 #include <stdint.h>
 
 #include <algorithm>
 #include <cmath>
@@ skipping 629 matching lines @@
   // Overridden from ButtonListener.
   void ButtonPressed(views::Button* sender, const ui::Event& event) override {
     if (sender->tag() == fullscreen_index_) {
       menu()->CancelAndEvaluate(menu_model(), sender->tag());
     } else {
       // Zoom buttons don't close the menu.
       menu_model()->ActivatedAt(sender->tag());
     }
   }
 
-  // Overridden from AppMenuObserver.
-  void AppMenuDestroyed() override { AppMenuView::AppMenuDestroyed(); }

[Devlin, 2016/03/15 21:39:22]

Drive-by: this was a bit silly.

+ private:
+  content::WebContents* GetActiveWebContents() const {
+    return menu() ?
+        menu()->browser_->tab_strip_model()->GetActiveWebContents() :
+        nullptr;
+  }
 
- private:
   void OnZoomLevelChanged(const content::HostZoomMap::ZoomLevelChange& change) {
     UpdateZoomControls();
   }
 
   void UpdateZoomControls() {
-    WebContents* selected_tab =
-        menu()->browser_->tab_strip_model()->GetActiveWebContents();
+    WebContents* selected_tab = GetActiveWebContents();
     int zoom = 100;
     if (selected_tab) {
       auto zoom_controller =
           ui_zoom::ZoomController::FromWebContents(selected_tab);
       if (zoom_controller)
         zoom = zoom_controller->GetZoomPercent();
       increment_button_->SetEnabled(zoom <
                                     selected_tab->GetMaximumZoomPercent());
       decrement_button_->SetEnabled(zoom >
                                     selected_tab->GetMinimumZoomPercent());
     }
     zoom_label_->SetText(
         l10n_util::GetStringFUTF16Int(IDS_ZOOM_PERCENT, zoom));
 
     zoom_label_max_width_valid_ = false;
   }
 
   // Returns the max width the zoom string can be.
   int ZoomLabelMaxWidth() const {
     if (!zoom_label_max_width_valid_) {
       const gfx::FontList& font_list = zoom_label_->font_list();
       int border_width = zoom_label_->border()
                              ? zoom_label_->border()->GetInsets().width()
                              : 0;
 
       int max_w = 0;
 
-      WebContents* selected_tab =
-          menu()->browser_->tab_strip_model()->GetActiveWebContents();
+      WebContents* selected_tab = GetActiveWebContents();
       if (selected_tab) {
         auto zoom_controller =
             ui_zoom::ZoomController::FromWebContents(selected_tab);
         DCHECK(zoom_controller);
         // Enumerate all zoom factors that can be used in PageZoom::Zoom.
         std::vector<double> zoom_factors = ui_zoom::PageZoom::PresetZoomFactors(
             zoom_controller->GetZoomPercent());
         for (auto zoom : zoom_factors) {
           int w = gfx::GetStringWidth(
               l10n_util::GetStringFUTF16Int(IDS_ZOOM_PERCENT,
@@ skipping 587 matching lines @@
                                 0,
                                 BookmarkMenuDelegate::SHOW_PERMANENT_FOLDERS,
                                 BOOKMARK_LAUNCH_LOCATION_APP_MENU);
 }
 
 int AppMenu::ModelIndexFromCommandId(int command_id) const {
   CommandIDToEntry::const_iterator ix = command_id_to_entry_.find(command_id);
   DCHECK(ix != command_id_to_entry_.end());
   return ix->second.second;
 }