1122794 - Call SetResolutionAndScaleTo() instead of SetResolution() consistently in TabChild

Status: RESOLVED FIXED

(Core :: Panning and Zooming, defect)

Description

[Botond Ballo [:botond]]

Bug 1076241 introduced a new API for APZ to zoom a document: by using nsIDOMWindowUtils::SetResolutionAndScaleTo() instead of nsIDOMWindowUtils::SetResolution().

As part of that change, a compositor-side transform that was previously applied unconditionally, is now only applied if the SetResolutionAndScaleTo() API is used, meaning that zooming should now always be done with the SetResolutionAndScaleTo() API.

However, one call site in TabChild still uses SetResolution() [1]. I believe this is incorrect and should be using SetResolutionAndScaleTo() instead.

I have a hypothesis that this might be causing of bug 1122324.

[1] http://mxr.mozilla.org/mozilla-central/source/dom/ipc/TabChild.cpp?rev=9ddc69b3693a#981

Comment 1

[Botond Ballo [:botond]]

Attachment: bug1122794.patch

Comment 2

[Kartikaya Gupta (email:[e-mail])]

Comment on attachment 8550600 [details] [diff] [review]
bug1122794.patch

Review of attachment 8550600 [details] [diff] [review]:
-----------------------------------------------------------------

Make sure to rebase, it's GetPresShellResolution() now.

Comment 3

[Botond Ballo [:botond]]

Rebased and landed:

https://hg.mozilla.org/integration/mozilla-inbound/rev/6c8cf0eff888

Comment 4

[Phil Ringnalda (:philor)]

https://hg.mozilla.org/mozilla-central/rev/6c8cf0eff888

Comment 5

[Botond Ballo [:botond]]

Comment on attachment 8550600 [details] [diff] [review]
bug1122794.patch

NOTE: Please see https://wiki.mozilla.org/Release_Management/B2G_Landing to better understand the B2G approval process and landings.

[Approval Request Comment]
Bug caused by (feature/regressing bug #): 
  Bug 1076241.

User impact if declined: 
  I haven't spent a lot of time devising STR that demonstrate
  a problem, but the patch fixes an obvious mistake that can
  in principle lead to a page or app, including one that isn't
  zoomable, loading at an incorrect zoom in some cases.

Testing completed: 
  Baking on m-c since 2015-01-19.

Risk to taking this patch (and alternatives if risky): 
  Super-low risk. It's an obvious omission from bug 1076241
  where we updated other call sites of a function, but forgot
  this one.

String or UUID changes made by this patch:
  None.

Comment 6

[Ryan VanderMeulen [:RyanVM]]

Needs rebasing for b2g37 uplift. Also, should we take this on Aurora as well?

Comment 7

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-b2g37_v2_2/rev/680a3c864aef

Comment 8

[Botond Ballo [:botond]]

(In reply to Ryan VanderMeulen [:RyanVM UTC-5] from comment #6)
> Needs rebasing for b2g37 uplift. 

As it happens, the patch posted in this bug (as opposed to the one that landed) is the one that applies cleanly to b2g37, so there's nothing for me to post :)

> Also, should we take this on Aurora as well?

Discussed this on IRC. TabChild is only used in e10s scenarios, and B2G is the only platform that has e10s enabled by default, so no.