Exposes FlutterSurfaceView, and FlutterTextureView to FlutterActivity and FlutterFragment. (#41984, #47557) (#16552)

This reverts commit 8ec994b4.

The formatter didn't understand what was going on here and broke the
text. Changed these to use `<pre>{@code }</pre>` instead.

This reverts commit 6aacf5e7.

skiping tests in Safari. LUCI recipe for Mac is ready. this is the only step left for stopping us running unit tests in Safari (#16550)

Migrates to using os_log for app logging on iOS 13 and above, macOS
10.11 and above. On older platform, fall back to syslog(), which is what
we used previously.

This re-lands commit 78a89097 with a fix.
That commit was reverted in a61dbf2f.

Retained surfaces are being prematurely recycled.
Temporarily disabling them until they are reworked.

Looks like somehow the fix to move to static_cast didn't get merged.

This reverts commit 78a89097.

Migrates to using os_log for app logging on iOS 13 and above, macOS
10.11 and above. On older platform, fall back to syslog(), which is what
we used previously.