This is a regression issue broken in ‘M-70’ and below is the bisect info:
Good Build : 70.0.3504.0 (Revision : 5785110)
Bad Build : 70.0.3505.0 (Revision : 578873)

(Unable to narrow down the range using per-revision bisect, hence providing bisect using old script)

Narrow bisect URL :
https://chromium.googlesource.com/chromium/src/+log/a8117de4347200bd9e5fbe6eebf7fd024f5b170f..ef11a157a7ba06db29bdccec8b9991e3f20c9b32

Suspecting : r578563 ?

Alan@ : Could you please check whether this is caused with respect to your change, if not please help us in assigning it to the right owner.

Note : 
1. Able to reproduce issue on Linux(14.04 LTS) OS.
2. Issue is not observed in Mac(10.12.6, 10.13.1, 10.14, 10.13.6) OS and the right click action works as expected in 'Cast' overlay in mac.

Thank You..!

Stack trace for the crash id:
----------------------------
Thread 0 (id: 0x16d8) CRASHED [EXCEPTION_ACCESS_VIOLATION_READ @ 0x00000110 ] MAGIC SIGNATURE THREAD
Stack Quality84%Show frame trust levels
0x000007fed3392e5e	(chrome.dll + 0x00272e5e )	Browser::is_app()
0x000007fed509f177	(chrome.dll -render_view_context_menu.cc:1034 )	RenderViewContextMenu::AppendLinkItems()
0x000007fed509ebe8	(chrome.dll -render_view_context_menu.cc:756 )	RenderViewContextMenu::InitMenu()
0x000007fed4c07a61	(chrome.dll -render_view_context_menu_base.cc:179 )	RenderViewContextMenuBase::Init()
0x000007fed4793704	(chrome.dll -chrome_web_contents_view_delegate_views.cc:84 )	ChromeWebContentsViewDelegateViews::BuildMenu(content::WebContents *,content::ContextMenuParams const &)
0x000007fed47937bf	(chrome.dll -chrome_web_contents_view_delegate_views.cc:101 )	ChromeWebContentsViewDelegateViews::ShowContextMenu(content::RenderFrameHost *,content::ContextMenuParams const &)
0x000007fed404703f	(chrome.dll -web_contents_impl.cc:5030 )	content::WebContentsImpl::ShowContextMenu(content::RenderFrameHost *,content::ContextMenuParams const &)
0x000007fed3e84e49	(chrome.dll -render_frame_host_impl.cc:2227 )	content::RenderFrameHostImpl::OnContextMenu(content::ContextMenuParams const &)
0x000007fed3e84c1c	(chrome.dll -ipc_message_templates.h:146 )	IPC::MessageT<FrameHostMsg_ContextMenu_Meta,std::tuple<content::ContextMenuParams>,void>::Dispatch<content::RenderFrameHostImpl,content::RenderFrameHostImpl,void,void (content::RenderFrameHostImpl::*)(const content::ContextMenuParams &)>
0x000007fed37556c5	(chrome.dll -render_frame_host_impl.cc:1069 )	content::RenderFrameHostImpl::OnMessageReceived(IPC::Message const &)
0x000007fed3754db8	(chrome.dll -render_process_host_impl.cc:3114 )	content::RenderProcessHostImpl::OnMessageReceived(IPC::Message const &)
0x000007fed3754c9d	(chrome.dll -ipc_channel_proxy.cc:320 )	IPC::ChannelProxy::Context::OnDispatchMessage(IPC::Message const &)
0x000007fed314420b	(chrome.dll -task_annotator.cc:101 )	base::debug::TaskAnnotator::RunTask(char const *,base::PendingTask *)
0x000007fed3143c06	(chrome.dll -message_loop.cc:432 )	base::MessageLoop::RunTask(base::PendingTask *)
0x000007fed313d0f4	(chrome.dll -message_loop.cc:515 )	base::MessageLoop::DoWork()
0x000007fed323a458	(chrome.dll -message_pump_win.cc:171 )	base::MessagePumpForUI::DoRunLoop()
0x000007fed313cded	(chrome.dll -message_pump_win.cc:52 )	base::MessagePumpWin::Run(base::MessagePump::Delegate *)
0x000007fed313cb50	(chrome.dll -run_loop.cc:102 )	base::RunLoop::Run()
0x000007fed350173f	(chrome.dll -chrome_browser_main.cc:2092 )	ChromeBrowserMainParts::MainMessageLoopRun(int *)
0x000007fed3501543	(chrome.dll -browser_main_loop.cc:1034 )	content::BrowserMainLoop::RunMainMessageLoopParts()
0x000007fed35014ee	(chrome.dll -browser_main_runner_impl.cc:162 )	content::BrowserMainRunnerImpl::Run()
0x000007fed3da7515	(chrome.dll -browser_main.cc:47 )	content::BrowserMain(content::MainFunctionParams const &)
0x000007fed42e3c4e	(chrome.dll -content_main_runner_impl.cc:596 )	content::RunBrowserProcessMain(content::MainFunctionParams const &,content::ContentMainDelegate *)
0x000007fed42e4000	(chrome.dll -content_main_runner_impl.cc:947 )	content::ContentMainRunnerImpl::Run(bool)
0x000007fed3125977	(chrome.dll -main.cc:472 )	service_manager::Main(service_manager::MainParams const &)
0x000007fed3125577	(chrome.dll -content_main.cc:19 )	content::ContentMain(content::ContentMainParams const &)
0x000007fed3121d69	(chrome.dll -chrome_main.cc:101 )	ChromeMain
0x000000013f95372b	(chrome.exe -main_dll_loader_win.cc:201 )	MainDllLoader::Launch(HINSTANCE__ *,base::TimeTicks)
0x000000013f951698	(chrome.exe -chrome_exe_main_win.cc:230 )	wWinMain
0x000000013fa14c91	(chrome.exe -exe_common.inl:283 )	__scrt_common_main_seh
0x770259cc	(KERNEL32.dll + 0x000159cc )	BaseThreadInitThunk
0x7728383c	(ntdll.dll + 0x0005383c )	RtlUserThreadStart

1)This crash is first started on latest canary 64.0.3282.186 and seeing 1 from 1 different clients.
2)This crash seen on Windows>Browser and it is in 16th rank position.
3)This crash not seen on latest Dev build.

70.0.3508.0	4.31%	5  - Canary
68.0.3440.75	3.45%	4  - Beta & Stable

Link to the list of builds:
---------------------------
https://crash.corp.google.com/browse?q=product_name%3D%27Chrome%27+AND+expanded_custom_data.ChromeCrashProto.ptype%3D%27browser%27+AND+expanded_custom_data.ChromeCrashProto.magic_signature_1.name%3D%27RenderViewContextMenu%3A%3AAppendLinkItems%27#-productname:1000,productversion:110,-magicsignature:50,-magicsignature2:50,-stablesignature:50,-magicsignaturesorted:50

Thank You!

Adding release blocker label for this issue.Please reduce priority or remove if not the case.

Thank You!

Looks like a missing null check, fix incoming. This probably affects ChromeOS as well.

Confirmed this affects ChromeOS which enabled DesktopPWAWindowing in M67.
The crash server shows no ChromeOS instances of this crash so we can probably skip merging the fix.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0ea2267a7cefa49ffd3f3080dcea241d9bbcdfd7

commit 0ea2267a7cefa49ffd3f3080dcea241d9bbcdfd7
Author: Alan Cutter <alancutter@chromium.org>
Date: Thu Aug 02 01:57:37 2018

Fix crash when right clicking link in CastUI

This CL adds a null check to RenderViewContextMenu::AppendLinkItems()
ensuring we have an associated Browser before attempting to use it.

Bug:  869280 
Change-Id: Ib1ffecd9dfbe27fb4fc6f6c77762c6337c36d4d4
Reviewed-on: https://chromium-review.googlesource.com/1158110
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Commit-Queue: Alan Cutter <alancutter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580029}
[modify] https://crrev.com/0ea2267a7cefa49ffd3f3080dcea241d9bbcdfd7/chrome/browser/DEPS
[modify] https://crrev.com/0ea2267a7cefa49ffd3f3080dcea241d9bbcdfd7/chrome/browser/renderer_context_menu/render_view_context_menu.cc
[modify] https://crrev.com/0ea2267a7cefa49ffd3f3080dcea241d9bbcdfd7/chrome/browser/renderer_context_menu/render_view_context_menu.h
[modify] https://crrev.com/0ea2267a7cefa49ffd3f3080dcea241d9bbcdfd7/chrome/browser/renderer_context_menu/render_view_context_menu_browsertest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0a26ad31ea97b1f1e9354502fc172c08310931a4

commit 0a26ad31ea97b1f1e9354502fc172c08310931a4
Author: Findit <findit-for-me@appspot.gserviceaccount.com>
Date: Thu Aug 02 06:50:00 2018

Revert "Fix crash when right clicking link in CastUI"

This reverts commit 0ea2267a7cefa49ffd3f3080dcea241d9bbcdfd7.

Reason for revert:

Findit (https://goo.gl/kROfz5) identified CL at revision 580029 as the
culprit for failures in the build cycles as shown on:
https://findit-for-me.appspot.com/waterfall/culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyRAsSDVdmU3VzcGVjdGVkQ0wiMWNocm9taXVtLzBlYTIyNjdhN2NlZmE0OWZmZDNmMzA4MGRjZWEyNDFkOWJiY2RmZDcM

Sample Failed Build: https://ci.chromium.org/buildbot/chromium.memory/Linux%20CFI/9359

Sample Failed Step: not_site_per_process_browser_tests

Original change's description:
> Fix crash when right clicking link in CastUI
> 
> This CL adds a null check to RenderViewContextMenu::AppendLinkItems()
> ensuring we have an associated Browser before attempting to use it.
> 
> Bug:  869280 
> Change-Id: Ib1ffecd9dfbe27fb4fc6f6c77762c6337c36d4d4
> Reviewed-on: https://chromium-review.googlesource.com/1158110
> Reviewed-by: Avi Drissman <avi@chromium.org>
> Reviewed-by: Giovanni Ortuño Urquidi <ortuno@chromium.org>
> Commit-Queue: Alan Cutter <alancutter@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#580029}

Change-Id: Ie3a0067047c42fc8682ca8663eede8f1195afaed
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  869280 
Reviewed-on: https://chromium-review.googlesource.com/1159804
Cr-Commit-Position: refs/heads/master@{#580095}
[modify] https://crrev.com/0a26ad31ea97b1f1e9354502fc172c08310931a4/chrome/browser/DEPS
[modify] https://crrev.com/0a26ad31ea97b1f1e9354502fc172c08310931a4/chrome/browser/renderer_context_menu/render_view_context_menu.cc
[modify] https://crrev.com/0a26ad31ea97b1f1e9354502fc172c08310931a4/chrome/browser/renderer_context_menu/render_view_context_menu.h
[modify] https://crrev.com/0a26ad31ea97b1f1e9354502fc172c08310931a4/chrome/browser/renderer_context_menu/render_view_context_menu_browsertest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/692e32e418d6e11d99d4eab76f575a8bc13935ce

commit 692e32e418d6e11d99d4eab76f575a8bc13935ce
Author: Alan Cutter <alancutter@chromium.org>
Date: Fri Aug 03 01:32:14 2018

Reland: Fix crash when right clicking link in CastUI

This CL adds a null check to RenderViewContextMenu::AppendLinkItems()
ensuring we have an associated Browser before attempting to use it.

This is a reland of https://chromium-review.googlesource.com/c/chromium/src/+/1158110
without using TestWebContents (which results in a bad downcast).

Bug:  869280 
Change-Id: I6799f0c746c0cdca941e1235ac476f4e1d8a1f0e
Reviewed-on: https://chromium-review.googlesource.com/1160121
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Alan Cutter <alancutter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580405}
[modify] https://crrev.com/692e32e418d6e11d99d4eab76f575a8bc13935ce/chrome/browser/renderer_context_menu/render_view_context_menu.cc
[modify] https://crrev.com/692e32e418d6e11d99d4eab76f575a8bc13935ce/chrome/browser/renderer_context_menu/render_view_context_menu.h
[modify] https://crrev.com/692e32e418d6e11d99d4eab76f575a8bc13935ce/chrome/browser/renderer_context_menu/render_view_context_menu_browsertest.cc