50-80ms delay when closing a tab

[bradleyrichter]

Test plan

1. Have a large number of bookmarks
2. Open a few of those bookmarks
3. Close each, one at a time. Should close immediately

for more info, see #9191 (comment)

Original issue description

Adding to the appearance of sluggishness is the delay seen when closing a tab.

Click on the close button.

Notice how long it takes before it closes after mouse-up event.

Brave: 0.13.5
rev: 7373a01
Muon: 2.56.7
libchromiumcontent: 56.0.2924.87
V8: 5.6.326.50
Node.js: 7.4.0
Update Channel: dev
os.platform: darwin
os.release: 16.3.0
os.arch: x64

[netinhoteixeira]

I have the same issue.

[netinhoteixeira]

Brave 0.15.314
rev 75ffa36
Muon 3.0.202
libchromiumcontent 58.0.3029.110
V8 5.8.283.38
Node.js 7.9.0
Update Channel dev
os.platform darwin
os.release 16.6.0
os.arch x64

[bradleyrichter]

@ayumi is finishing up a fix on this. Will land very soon. See #9191.