1147223 - Fix wheel events not applying root scroll delta overrides

Status: RESOLVED FIXED

(Core :: Panning and Zooming, defect)

Description

[David Anderson [:dvander] - inactive, e-mail if emergency]

I messed up in bug 1141728. Windows has a default mousewheel.system_scroll_override_on_root_content.enabled value of true, with a delta multiplier of 2.0. Wheel events by default aren't going through APZ on Windows.

Easiest solution is to just honor the pref. This patch won't honor the extra gunk in nsWindow::OverrideSystemMouseScrollSpeed, but currently e10s doesn't honor it anyway since it goes through PuppetWidget.

I'm cleaning up the about:support detection of bad prefs after discovering this, since using HasUserPref() doesn't necessarily catch bad settings.

Comment 1

[David Anderson [:dvander] - inactive, e-mail if emergency]

Attachment: fix

Comment 2

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

Comment on attachment 8582778 [details] [diff] [review]
fix

Review of attachment 8582778 [details] [diff] [review]:
-----------------------------------------------------------------

I'd like to see this split into two patches for landing - first one does the APZ changes and removes the override_on_root_content pref from the gfxPlatform list; second one does the rest of the gfxPlatform changes.

::: gfx/thebes/gfxPrefs.h
@@ +338,5 @@
> +  DECL_GFX_PREF(Live, "mousewheel.system_scroll_override_on_root_content.enabled",
> +                                                               MouseWheelHasRootScrollDeltaOverride, bool, false);
> +  DECL_GFX_PREF(Live, "mousewheel.system_scroll_override_on_root_content.vertical.factor",
> +                                                               MouseWheelRootVScrollDeltaFactor, int32_t, 100);
> +  DECL_GFX_PREF(Live, "mousewheel.system_scroll_override_on_root_content.horizontal.factor",

alphabetize, horizontal should go before vertical.

Comment 3

[David Anderson [:dvander] - inactive, e-mail if emergency]

remote:   https://hg.mozilla.org/integration/mozilla-inbound/rev/e122d0043843
remote:   https://hg.mozilla.org/integration/mozilla-inbound/rev/1b0655f6b110
remote:   https://hg.mozilla.org/integration/mozilla-inbound/rev/07dc430fc6a0

w/ comments addressed (forgot to include the sorting one in the first push)

Comment 4

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/e122d0043843
https://hg.mozilla.org/mozilla-central/rev/1b0655f6b110