The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/cf95689a88664eb44716632cc7320d18ed3324ba

commit cf95689a88664eb44716632cc7320d18ed3324ba
Author: Trent Apted <tapted@chromium.org>
Date: Wed Nov 22 00:01:10 2017

Mac: Lazily populate bookmarks menus.

Currently the first time you press a key (any key) in WebContent
on Chrome Mac, Chrome makes a NSMenuItem for every bookmark you have,
and spawns tasks to convert each favicon. These then persist in memory
to service the Bookmarks menu on the menubar.

On my profile with ~1000 bookmarks, Chrome jumps from 95MB to 105MB
resident memory if I open about:blank and press a key. And there is
noticeable lag. Each browser window's App menu also has a full
bookmarks tree, populated once the 'Bookmarks' item is hovered over,
and persisted in memory; taking up about 800kB (approximately doubling
the browser process memory used by a single-tab browser window).

In order to populate these lazily, the bookmarks menu must respond `NO`
to -[NSMenuDelegate menuHasKeyEquivalent:..]. Otherwise the menu is
fully populated on the first key event to see if any bookmark titles
match the event. With this in place, we can leave all bookmarks
submenus empty, but set a delegate that AppKit uses to populate the
menu when the user first shows it.

Bug:  33102 ,  647183 ,  733921 ,  786845 
Change-Id: Idc0a28cf9483f7161dc3fbe9bd6cda717e65de98
Reviewed-on: https://chromium-review.googlesource.com/778644
Commit-Queue: Trent Apted <tapted@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#518459}
[modify] https://crrev.com/cf95689a88664eb44716632cc7320d18ed3324ba/chrome/browser/app_controller_mac.mm
[modify] https://crrev.com/cf95689a88664eb44716632cc7320d18ed3324ba/chrome/browser/app_controller_mac_browsertest.mm
[modify] https://crrev.com/cf95689a88664eb44716632cc7320d18ed3324ba/chrome/browser/ui/cocoa/app_menu/app_menu_controller.mm
[modify] https://crrev.com/cf95689a88664eb44716632cc7320d18ed3324ba/chrome/browser/ui/cocoa/bookmarks/bookmark_menu_bridge.h
[modify] https://crrev.com/cf95689a88664eb44716632cc7320d18ed3324ba/chrome/browser/ui/cocoa/bookmarks/bookmark_menu_bridge.mm
[modify] https://crrev.com/cf95689a88664eb44716632cc7320d18ed3324ba/chrome/browser/ui/cocoa/bookmarks/bookmark_menu_bridge_unittest.mm
[modify] https://crrev.com/cf95689a88664eb44716632cc7320d18ed3324ba/chrome/browser/ui/cocoa/bookmarks/bookmark_menu_cocoa_controller.h
[modify] https://crrev.com/cf95689a88664eb44716632cc7320d18ed3324ba/chrome/browser/ui/cocoa/bookmarks/bookmark_menu_cocoa_controller.mm