Currently, the css for a separator is something like { height: 1px; background-color: ... }.
But its rendering depends on its position on the screen.
So instead of setting the height to 1px, we just set something like { border-top: 1px solid ...; },
this way the final rendering is exactly the same for all the separators.
This code is quite old and has been moved/re-factored a few times over the years, however we can simplify this even further since we don't actually need a function to determine what NetworkStream-implementation to use.
After the removal of 'unsafe-eval' CSP in #18651, WebAssembly fails to
load, resulting in issues such as seen in #18457.
Manifest Version 3 does not allow 'unsafe-eval', does accept the more
specific 'wasm-unsafe-eval' as of Chrome 103. Note that manifest.json
already sets minimum_chrome_version to 103.
This patch also adds `object-src 'self'` because it was required until
Chrome 110. As of Chrome 111, the default is `object-src 'self'` and
`object-src` is no longer required. We could drop `object-src` in the
future, but for now we need to include it to support Chrome 103 - 110.
Note that the textContent is returned in "chunks" from the API, through the use of `ReadableStream`s, and on the main-thread we're (normally) using just one temporary canvas in order to measure the size of the textLayer `span`s; see the [`#layout`](5b4c2fe1a8/src/display/text_layer.js (L396-L428)) method.
*Order of events, for parallel textLayer rendering:*
1. Call [`render`](5b4c2fe1a8/src/display/text_layer.js (L155-L177)) of the textLayer for page A.
2. Immediately call `render` of the textLayer for page B.
3. The first text-chunk for pageA arrives, and it's parsed/layout which means updating the cached [fontSize/fontFamily](5b4c2fe1a8/src/display/text_layer.js (L409-L413)) for the textLayer of page A.
4. The first text-chunk for pageB arrives, which means updating the cached fontSize/fontFamily *for the textLayer of page B* since this data is unique to each `TextLayer`-instance.
5. The second text-chunk for pageA arrives, and we don't update the canvas-font since the cached fontSize/fontFamily still apply from step 3 above.
Where this potentially breaks down is between the last steps, since we're using just one temporary canvas for all measurements but have *individual* fontSize/fontFamily caches for each textLayer.
Hence it's possible that the canvas-font has actually changed, despite the cached values suggesting otherwise, and to address this we instead cache the fontSize/fontFamily globally through a new (static) helper method.
*Note:* Includes a basic unit-test, using dummy text-content, which fails on `master` and passes with this patch.
Finally, pun intended, ensure that temporary textLayer-data is cleared *before* the `render`-promise resolves to avoid any intermittent problems in the unit-tests.
Fix regression from #18711. `urlFilter` is a key of `condition`, not of
the `rule`. Consequently, the feature detection method failed to detect
the availability of the feature in Chrome 128+.
