Issue 781968  has been merged into this issue.

If no textarea is handy, create one by navigating to data:text/html,<textarea>

Do we have a bisect?

Able to reproduce the issue on Mac os 10.12.6 using chrome M64 #64.0.3261.0 and M62 #62.0.3202.89.

This is a regression issue broken in M61 and is reproduce on Mac OS .

Good Build : 61.0.3150.0 
Bad Build : 61.0.3152.0

You are probably looking for a change made after 484706 (known good), but no later than 484708 (first known bad).

CHANGELOG URL:

The script might not always return single CL as suspect as some perf builds might get missing due to failure.

  https://chromium.googlesource.com/chromium/src/+log/d228d5d9f15e1f93415ccee3196aa43b745c1cb3..2cd5186ee730c77dcf5e8699d67d8796ac7e7aa6

@Unable to find the possible suspect from the above CL , Could someone help us in assigning it to the concern owner.

Thansk

fwiw, 60.0.3112.101 produces the panel. 

bisect gives "You are probably looking for a change made after 484697 (known good), but no later than 484710 (first known bad)."
https://chromium.googlesource.com/chromium/src/+log/01b4e652995e1255782dc157b7af7e14cd109127..b5ac971cfbf3afa2230534369912bffccefb0fc1

Likely candidate is the WidgetInputHandler change by dtapuska

Here is what I think the problem is: The change replaces the second (value) parameter for EditCommand with an Optional<string>. And then treats the empty string and nullptr as the same.  (specifically, in EditCommandImp and doCommandBySelector)

Except... they aren't. 

The nullptr version ends up calling Editor::ExecuteCommand(const String& command_name). The other one calls the dual-parameter Editor::ExecuteCommand(const String& command_name, const String& value)

And now... drumroll - the first one supports ToggleSpellPanel command, the second the showGuessPanel command. The selector is named -showGuessPanel. Pre-change, that invoked the two-parameter version with ("showGuessPanel","") - and all was well.

After the change, it instead gets a nullptr for the value, which routes into the one-parameter version - and that one doesn't know about showGuessPanel.

I have no idea why we need two different names for this. I'd strongly suggest handling both names in both functions, or, better, collapsing both functions into one - since base::Optional is now available in WebKit (as WTF::Optional)

+dtapuska to confirm

Adding M-63 milestone since M62 is already in stable.

Route to Blink>Input, since this issue is happend after introducing WidgetInputHandler.

Note: Displaying spell check panel is controlled by SpellCheckPanel in
//src/components/spellcheck/renderer/spellcheck_panel.cc

Sending over to groby@ as patch is in the works.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5b96839ae07f6309a515e0a4ed9bdc8c4f9b3fe9

commit 5b96839ae07f6309a515e0a4ed9bdc8c4f9b3fe9
Author: Rachel Blum <groby@chromium.org>
Date: Sat Nov 18 03:37:38 2017

[spellcheck,OSX] Fix keyboard shortcut for spellcheck panel

The spellcheck panel on OSX can be invoked via two editor commands:
ToggleSpellPanel, and showGuessPanel. It used to be that one was invoked
as an EditorCommand with no parameter, and the second as a command with
empty string as parameter.

This changed at some point. As an additional hurdle, editor commands
without a parameter also get a capital letter as initial (mandatory).

The fix here removes the invokation via the selector name - a.k.a.
showGuessPanel - and renames that to ToggleSpellPanel.

It does *not* address the issue of two separate invokation paths.
(That is a follow-up CL, since it might require rollback)

BUG= 781971 

Change-Id: I2023c5d3b91f491706ea2401c9cd03dbd87ae71e
Reviewed-on: https://chromium-review.googlesource.com/759658
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Dave Tapuska <dtapuska@chromium.org>
Commit-Queue: Rachel Blum <groby@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517692}
[modify] https://crrev.com/5b96839ae07f6309a515e0a4ed9bdc8c4f9b3fe9/content/browser/renderer_host/render_widget_host_view_mac_editcommand_helper.mm
[modify] https://crrev.com/5b96839ae07f6309a515e0a4ed9bdc8c4f9b3fe9/third_party/WebKit/Source/core/editing/commands/EditorCommand.cpp

Verified the issue on Mac os 10.12.6 using chrome M64 #64.0.3273.0 and issue is fixed.

The Spelling and Grammar panel is shown. Adding TE-Verified labels.

Thanks!

Guess this can be closed?

AFAICT, yes - shrike@ wanted additional test coverage, but that's handled in  bug #782836 , also closed