EditPage uses a ton of global objects ($wgOut, $wgUser, etc.). These should be replaced with the appropriate RequestContext function instead.
A `getContext()` function and `$this->context` member variable were added in {841c4076574bc2f390092ea6ae85c9248a999008}.
Then, four commits were made to switch global objects out for context equivalents (1000 line chunks):
* {f2f810181aa4188053da2af94faa6e3bad33d1a3}
* {afa630749a393114a5df0921f75590a8ca189c91}
* {27fd11095213eaf2b3b5d2e21a93b6ee03c3b004}
* {589cadedf31787e75c9f83b3c4f05c79397dd4cc}
These were reverted in {5ce43a98613303fac6bad6e6c7663c478f726cd2} due to breakage in LiquidThreads: {T143889}.
We need to check other Wikimedia-deployed extensions and then re-apply the de-globalization change.
[x] `$wgAjaxEditStash`: 2 uses
[x] `$wgAllowUserCss`: 2 uses
[x] `$wgAllowUserJs`: 2 uses
[x] `$wgBrowserBlackList`: 3 uses - gone with {T67297}
[x] `$wgContentHandlerUseDB`: 3 uses
[ ] `$wgContLang`: 5 uses - OK, no context based replacement
[ ] `$wgEnableUploads`: 1 use - static
[ ] `$wgForeignFileRepos`: 2 uses - static
[x] `$wgLang`
[x] `$wgMaxArticleSize`: 4 uses
[x] `$wgOut`: 2 uses - remaining uses will go away with {T30856}
[ ] `$wgParser`: 8 uses - OK, no context based replacement
[x] `$wgPreviewOnOpenNamespaces`: 3 uses
[x] `$wgRawHtml`: 2 uses
[x] `$wgRequest`: 13 uses
[ ] `$wgRightsText`: 3 uses - static
[ ] `$wgSpamRegex`: 4 uses - static
[ ] `$wgSummarySpamRegex`: 3 uses - static
[ ] `$wgTitle`: 3 uses
[x] `$wgUseMediaWikiUIEverywhere`: 2 uses
[x] `$wgUser`