Crash in sidebar::SidebarService::GetNotAddedDefaultSidebarItems

[iefremov]

Test plan

1. Enable sidebar via brave://flags/#sidebar
2. Restart when prompted
3. Confirm app relaunches without crash after toggling brave://flags/#sidebar to true

Description

[ 00 ] <name omitted>
[ 01 ] <name omitted>
[ 02 ] <name omitted>
[ 03 ] sidebar::SidebarService::GetNotAddedDefaultSidebarItems() const
[ 04 ] sidebar::SidebarModel::IsSidebarHasAllBuiltiInItems() const
[ 05 ] SidebarControlView::SidebarControlView(BraveBrowser*)
[ 06 ] SidebarContainerView::Init()
[ 07 ] BraveBrowserView::InitSidebar()
[ 08 ] BraveBrowser::BraveBrowser(Browser::CreateParams const&)
[ 09 ] SessionRestoreImpl::CreateRestoredBrowser(Browser::Type, gfx::Rect, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, bool, ui::WindowShowState, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, int)
[ 10 ] SessionRestoreImpl::ProcessSessionWindows(std::__1::vector<std::__1::unique_ptr<sessions::SessionWindow, std::__1::default_delete<sessions::SessionWindow> >, std::__1::allocator<std::__1::unique_ptr<sessions::SessionWindow, std::__1::default_delete<sessions::SessionWindow> > > >*, SessionID, std::__1::vector<SessionRestoreDelegate::RestoredTab, std::__1::allocator<SessionRestoreDelegate::RestoredTab> >*, int*, int*)
[ 11 ] SessionRestoreImpl::ProcessSessionWindowsAndNotify(std::__1::vector<std::__1::unique_ptr<sessions::SessionWindow, std::__1::default_delete<sessions::SessionWindow> >, std::__1::allocator<std::__1::unique_ptr<sessions::SessionWindow, std::__1::default_delete<sessions::SessionWindow> > > >*, SessionID)
[ 12 ] SessionRestoreImpl::Restore()

https://brave.sp.backtrace.io/p/brave/triage?filters=((callstack.functions%2Ccontains%2Csidebar)%2Cptype%3Dbrowser%2Cver%3E%3D%2291%22)&aggregations=((guid%2Cunique)%2C(classifiers%2Chead))&similarity=false

[iefremov]

cc @simonhong

[stephendonner]

Sadly (sorry!) this is fallout from my "simple string change" over in #16709.

[bsclifton]

Fixed with brave/brave-core#9347

[stephendonner]

Verified FIXED using the testplan here with build

Brave	1.28.70 Chromium: 92.0.4515.81 (Official Build) nightly (x86_64)
Revision	dba3af0a9a48954c8b188bc641e651580b7cb7b5-refs/branch-heads/4515@{#1162}
OS	macOS Version 11.4 (Build 20F71)

Steps:

1. clean profile
2. launched Brave
3. enabled sidebar via brave://flags/#sidebar
4. restarted when prompted
5. confirmed Brave relaunches without crash after toggling brave://flags/#sidebar to true

---

Verification passed on

Brave | 1.28.89 Chromium: 92.0.4515.107 (Official Build) dev (64-bit)
-- | --
Revision | 87a818b10553a07434ea9e2b6dccf3cbe7895134-refs/branch-heads/4515@{#1634}
OS | Windows 10 OS Version 2004 (Build 19041.1110)

Confirmed there is no crash when Brave Talk is selected from the sidebar menu

---

Verification passed on

Brave	1.28.89 Chromium: 92.0.4515.107 (Official Build) dev (64-bit)
Revision	87a818b10553a07434ea9e2b6dccf3cbe7895134-refs/branch-heads/4515@{#1634}
OS	Ubuntu 18.04 LTS

No crash

[GeetaSarvadnya]

@simonhong I don't see the Enable Sidebar flag under brave://flags in Brave Beta 1.28.91 but it exists in Dev 1.28.89 version

[simonhong]

@GeetaSarvadnya Sidebar feature is not available for beta/stable channel now.