Reland "Make AppMenuModel keep most submenus in a vector."

This reverts commit dfd0e0a0.

Reason for revert: This reverted half the change, leaving trunk broken,
see https://crbug.com/1020524

Original change's description:
> Revert "Make AppMenuModel keep most submenus in a vector."
> 
> This reverts commit 849315dd.
> 
> Reason for revert: [sheriff] does not build on Mac per builder (https://ci.chromium.org/p/chrome/builders/ci/mac-builder-perf/125702)
> 
> Original change's description:
> > Make AppMenuModel keep most submenus in a vector.
> > 
> > They are only needed for ownership, so no need to give them names and concrete
> > types. Removes some forward declarations from the header and serendipitously
> > happens to remove GOOGLE_CHROME_BUILD from the header as well.
> > 
> > No intended behavior change.
> > 
> > Bug: 961769
> > Change-Id: Ibaaf3375bd9d367b4cc83b9a8ec3e64193750a69
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1894032
> > Commit-Queue: Robert Sesek <rsesek@chromium.org>
> > Auto-Submit: Nico Weber <thakis@chromium.org>
> > Reviewed-by: Robert Sesek <rsesek@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#711431}
> 
> TBR=thakis@chromium.org,rsesek@chromium.org
> 
> Change-Id: Id7abf98d32a424fdf3d8d0638c9967931eec30a8
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 961769
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1893867
> Reviewed-by: Armando Miraglia <armax@chromium.org>
> Commit-Queue: Armando Miraglia <armax@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#711663}

TBR=thakis@chromium.org,rsesek@chromium.org,armax@chromium.org

Change-Id: Iae16e60dadcda2a91ff8207e214f18989caf5a53
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 961769
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1895640Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711703}

chrome/browser/ui/toolbar/app_menu_model.cc

@@ -751,10 +751,10 @@ void AppMenuModel::Build() {
   AddSeparator(ui::NORMAL_SEPARATOR);
 
   if (!browser_->profile()->IsOffTheRecord()) {
-    recent_tabs_sub_menu_model_ =
-        std::make_unique<RecentTabsSubMenuModel>(provider_, browser_);
+    sub_menus_.push_back(
+        std::make_unique<RecentTabsSubMenuModel>(provider_, browser_));
     AddSubMenuWithStringId(IDC_RECENT_TABS_MENU, IDS_HISTORY_MENU,
-                           recent_tabs_sub_menu_model_.get());
+                           sub_menus_.back().get());
   }
   AddItemWithStringId(IDC_SHOW_DOWNLOADS, IDS_SHOW_DOWNLOADS);
   if (!browser_->profile()->IsGuestSession()) {
@@ -801,9 +801,9 @@ void AppMenuModel::Build() {
   }
 #endif
 
-  tools_menu_model_ = std::make_unique<ToolsMenuModel>(this, browser_);
+  sub_menus_.push_back(std::make_unique<ToolsMenuModel>(this, browser_));
   AddSubMenuWithStringId(IDC_MORE_TOOLS_MENU, IDS_MORE_TOOLS_MENU,
-                         tools_menu_model_.get());
+                         sub_menus_.back().get());
   AddSeparator(ui::LOWER_SEPARATOR);
   CreateCutCopyPasteMenu();
   AddSeparator(ui::UPPER_SEPARATOR);
@@ -813,8 +813,8 @@ void AppMenuModel::Build() {
 // 'About' item has been moved to this submenu, it's reinstated here for
 // Chromium builds.
 #if BUILDFLAG(GOOGLE_CHROME_BRANDING)
-  help_menu_model_ = std::make_unique<HelpMenuModel>(this, browser_);
-  AddSubMenuWithStringId(IDC_HELP_MENU, IDS_HELP_MENU, help_menu_model_.get());
+  sub_menus_.push_back(std::make_unique<HelpMenuModel>(this, browser_));
+  AddSubMenuWithStringId(IDC_HELP_MENU, IDS_HELP_MENU, sub_menus_.back().get());
 #else
 #if defined(OS_CHROMEOS)
   if (base::FeatureList::IsEnabled(chromeos::features::kSplitSettings))

chrome/browser/ui/toolbar/app_menu_model.h

@@ -21,7 +21,6 @@
 class AppMenuIconController;
 class BookmarkSubMenuModel;
 class Browser;
-class RecentTabsSubMenuModel;
 
 namespace {
 class MockAppMenuModel;
@@ -180,7 +179,6 @@ class AppMenuModel : public ui::SimpleMenuModel,
   void CreateZoomMenu();
 
  private:
-  class HelpMenuModel;
   friend class ::MockAppMenuModel;
 
   bool ShouldShowNewIncognitoWindowMenuItem();
@@ -213,19 +211,11 @@ class AppMenuModel : public ui::SimpleMenuModel,
   // Label of the zoom label in the zoom menu item.
   base::string16 zoom_label_;
 
-#if defined(GOOGLE_CHROME_BUILD)
-  // Help menu.
-  std::unique_ptr<HelpMenuModel> help_menu_model_;
-#endif
-
-  // Tools menu.
-  std::unique_ptr<ToolsMenuModel> tools_menu_model_;
-
   // Bookmark submenu.
   std::unique_ptr<BookmarkSubMenuModel> bookmark_sub_menu_model_;
 
-  // Recent Tabs submenu.
-  std::unique_ptr<RecentTabsSubMenuModel> recent_tabs_sub_menu_model_;
+  // Other submenus.
+  std::vector<std::unique_ptr<ui::SimpleMenuModel>> sub_menus_;
 
   ui::AcceleratorProvider* provider_;  // weak