Android seems to do this by default. This way, if you select a table cell it will read the content of that cell.

* Fix crash in iOS accessbility

Previously, whenever an action would remove the focused element from the screen the app would crash. This change tells iOS to focus the first on-screen element after every change to the semantics tree. This avoids the crash.

In a future iteration, we should tell iOS which element it needs to focus by looking at the sematnics tree (instead of leaving it up to the iOS).

* Better handle the case were the focused element stays on the screen

* review comments

Fixes https://github.com/flutter/flutter/issues/9439

Use AudioServicesPlaySystemSound instead of AudioServicesPlayAlertSound.
This avoids the potential of a system beep on devices without support
for haptic feedback.

Scrollable elements can now be scrolled in accessibility mode and they scroll in the right direction.

Note: App crashes right after scroll finishes (that's a separate problem as the app currently crashes after every action performed in accessibility mode).

* AX fixes for iOS

With this, the accessibility frame (for VoiceOver, etc.) is drawn at the right position around a widget.

* review comments

Check incoming text editing state and only fire textWillChange:,
textDidChange:, selectionWillChange:, selectionDidChange: when the text
or selection actually changes.

On selectionWillChange: in a text field where auto-correct is enabled,
iOS will attempt to auto-correct the word preceding the cursor. This
change also updates the text before calling selectionWillChange: to
prevent auto-correction on the preceding value of the text field.

This will ensure that the engine is not broken by a future
skia roll.

The new pattern is needed to support the migration to service namespaces.

The core problem was multiplying matrices the wrong way around.

While I was there I did some minor cleanup. I think that may have
fixed another bug relating to A11Y turning on or off improperly, but
since I never figured out the steps to reproduce, it's hard to tell.

Fixes https://github.com/flutter/flutter/issues/7205
Fixes https://github.com/flutter/flutter/issues/10059 (maybe)

Having the device pixel ratio of the test shell be 1.0x makes it
unlikely that we will catch errors relating to mishandling of the
device pixel ratio in the test shell.

This patch arbitrarily increases the device pixel resolution while
keeping the logical resolution the same.

Skia doesn't actually create the image if we don't supply a color space.

Fixes https://github.com/flutter/flutter/issues/9473

Handle willChangeFrame to handle keyboard show, resize, reposition
(split, move floating keyboard) events. Handle willBeHidden events for
keyboard dismissal.

Fixes incorrect bottom padding introduced in
f2581c9b due to didChangeFrame
notification firing after willBeHidden on keyboard dismissal.

We still don't get IME text, but at least we don't crash.

This patch wires Mozart's text input system to flutter/textinput. This patch
doesn't fully work yet because the Mozart side isn't fully implemented.

Disable info debug messages from the layers to cut down log spam.

* Update Skia revision to 7120b2d577d3aab1f51c5af1530a68c57ca51696.
* Update licenses.
* Account for content handler updates.