This reverts commit 2627634b.

Reland "Bump simulator version in IosUnitTests & scenario app in preparation for luci xcode 11 migration (#15316)", Reverted in #15313

This reverts commit 8ed688f7.

Revert "Bump simulator version in IosUnitTests & scenario app in preparation for luci xcode 11 migration (#15154)" (#15313)

This reverts commit 3a9121b9.

Bump simulator version in IosUnitTests & scenario app in preparation for luci xcode 11 migration (#15154)

This reverts commit f456423c.

This is being reverted because it caused flutter/flutter#45098
(images don't load on iOS).

This reverts commit 2dcfaaeb.

This reverts commit 618e6666.

Revert "Always use `IOSGLContextSwitch` to access EAGLContexts to prevent plugins from polluting Flutter's EAGLContext (#13314)" (#13753)

Always use `IOSGLContextSwitch` to access EAGLContexts to prevent plugins from polluting Flutter's EAGLContext (#13314)

When gr context is changed (this happens when sending the app to the background and then to the foreground) we need to update it for all the platform view overlay surfaces.

The update logic was caching the previous gr context to figure if it had to be updated, but after updating it for a given overlay we were updating the cached context. In apps with multiple platform views this will result in overlays with a stale gr context.

This fixes flutter/flutter#36437
And I believe it should fix flutter/flutter#36999 as well (though I don't have repro code to verify).

Having 2 or more platform views simultaneously in the layer tree was crashing immediately on iOS with GL backend.

This regressed in #11070 which passed gl_context to a function in a loop using std::move (which meant on the second iteration the caller is no longer the owner of the field).

I added a scenarios_app test, though this test doesn't run on a physical device on CI so it would have only caught the problem when running locally (flutter/flutter#43852).

This reverts commit b73cfdad.