[mac triage] this is working for me in the 53.0.2768.0 canary that just came out (admittedly, it's an Magic Trackpad, not a macbook). That's r399800, so that's a pretty small bisect

https://chromium.googlesource.com/chromium/src/+log/53.0.2768.0..23fa660b47e7a5fdadd6303eb966cc31a51d4b5e?pretty=fuller&n=10000

Nothing there is interesting though, except (perhaps coincidentally) r399804 itself.

But r399806 is right nearby: "Use the new zoom state for touchpad pinch zoom". Curious? (unlikely that it's a linux change AFAIK).

Can you try the latest canary?

Double-tap to zoom was working, but pinch-zoom not.

I can confirm it is working on today's Canary 53.0.2768.0, so I'll try a new dev build.

Pinch zoom is still not working in my local Release build.  ccameron@ also confirmed.

I just built top of tree on a MBP, and pinch zooming appears to be working fine. I'm happy to look into/bisect this problem if it's reproducible. ccameron@, maybe tomorrow when you're in MTV you can show me the problematic behavior?

It's back to working on Canary for me. I'll verify a local build, then close if it's alive again.

Does not work on touchscreen windows devices

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b4480ddac51c6c5e195ca5a14f5ef35a27b9865a

commit b4480ddac51c6c5e195ca5a14f5ef35a27b9865a
Author: ananta <ananta@chromium.org>
Date: Fri Jul 22 20:10:56 2016

Fix touchpad zoom on touchscreen Windows devices.

TouchPad pinch to zoom on Windows typically works via a WM_MOUSEWHEEL
message with the CONTROL flag in wParam and varying deltas. On touchscreen
Windows devices like Surface, the WM_MOUSEWHEEL event is flagged as a
synthesized message occurring due to a touch.

I think it is safe to allow all WM_MOUSEWHEEL events to be processed by
ignoring the touch flag as they don't appear to get synthesized via
standard touch scrolls.

Changes in this patch are as below:

1. Ignore the touch flag on WM_MOUSEWHEEL and WM_MOUSEHWHEEL messages.
2. Removed dead code in hwnd_message_handler.cc/.h which tried to set
   scroll styles on the window.

BUG=620182

Review-Url: https://codereview.chromium.org/2172843002
Cr-Commit-Position: refs/heads/master@{#407240}

[modify] https://crrev.com/b4480ddac51c6c5e195ca5a14f5ef35a27b9865a/ui/views/win/hwnd_message_handler.cc
[modify] https://crrev.com/b4480ddac51c6c5e195ca5a14f5ef35a27b9865a/ui/views/win/hwnd_message_handler.h

->ananta cause they are checking in changes on this.

Mac issue can be closed.

Able to reproduce on latest tree local build (r425759), Mac 10.11.6. 
Two finger pinch zoom doesn't work.

However not able to reproduce on Canary 56.0.2891.0.

Is this related to Official build or something?

erik, can you repro in a local build? comment #12 seems bizarre. 

It seems this issue is related to the macOS SDK version. When Chromium is built with 10.10 SDK everything works fine, but then 10.12 is used — pinch zooming doesn't work anymore.

Unassigning all bugs for ananta@chromium.org