This reverts commit 2ae09caa.

This shouldn't break our tests as
https://github.com/flutter/gallery/issues/275 is closed.

* Remove opacity from check and add test

ensure that the terminal handler checks if the service protocol is enabled before calling debug toggle brightness. Also removes globals from TerminalHander and test cases.

Fixes #65477

This reverts commit 48ce83a8.

* b49de93b3 Create an ImageHandle wrapper (flutter/engine#21057)

* b0fb2c8a9 Roll Skia from 7b97b3cb2bd0 to 59b2a92c96ba (4 revisions) (flutter/engine#21365)

Otherwise the heuristics we have may decide to skip running pub. We should consider reducing the number of dimensions of caching here to a single check optimized for the run/test case.

* [Docs] [Icons] Updating dart doc styles to recognize more styles of icons. All the 4 icon styles we support have to be pulled from 4 individual web fonts when we show the html page for api docs.

* Better documentation and that special awful case.

* Couple more places to remove.

Complete the migration to the TextSelectionTheme by deprecating the opt-in flag and text selection properties in ThemeData. (#66482)

* Fixes typos in showDialog documentation

* disable pub lints

* + comments

Registering the service worker immediately after the documented has loaded may cause SW initialization to compete with framework initialization. It was recommended to us that we defer the service worker setup until after the framework is done with setup, which should be sometime after the first frame.

To implement this, I augmented the binding setup to dispatch an event on the document after the binding has initialized. I don't see any obvious risks with this setup.

Fixes #66066

This should be a mostly non breaking change for hot reload workflows that improves performance, but if you see anything odd with hot reload behavior on master please file a bug. This feature can also be disabled without any changes to the SDK with flutter config --no-single-widget-reload-optimization 

Delete the destination directory for the web sdk before copying the new contents. This might fix an error where the OS refuses to overwrite the files on dev

* migrate some cupertino files to nullsafety

* address review comments