This contains some fixes for Fuchsia and I'd like to keep the version
of Dart used in fuchsia and flutter builds consistent. Should have no
other impactful changes for Flutter.

Mozart ADD, REMOVE and HOVER phases were going through the default value
of Blink's Cancel type, causing inconsistencies.

Bug: US-157

This change eliminates two previous assumptions:
1. If a Flutter view is embedded in a parent view, that the parent view
   controller would apply any status bar padding necessary.
2. That we should not apply padding unless the flutter view is
   fullscreen.

A simple case where the first assumption fails to hold is a Flutter view
embedded in a UINavigationController with a hidden toolbar. A simple
case where the second assumption fails to hold is a view in a window
whose top overlaps the status bar but isn't fullscreen.

Fixes https://github.com/flutter/flutter/issues/8084

I had added this initially as a means of making it easier to deal with OpenGL directly in Flow. However, we are moving away from dealing with the client rendering APIs directly. Instead, delegating everything to Skia. Besides, we only ever used this to log the GPU description in case of context setup failures. This has not proved to be useful so far. Also, having this in place is making it difficult to remove all dependencies on GL in Shell.

* New mozart input events.

* Adding TODO for keyrepeat

This applies commit 88441bfc0f712ad451784851bfcf0b0cc418ad75 from the
skia_rev_130a118cc68f8f9973e9572356011de378463fea branch to master so
master works in the Fuchsia build again.

Previously we had passed a local generator to flow::BitmapImageCreate /
SkImage::MakeFromGenerator, which takes ownership of the generator.
That generator in turn referenced an SkData backed by a local vector.
The result was an SkImage backed by a deleted buffer.

Merged iOS and Android font fallback mechanisms and push font discovery logic into skia

I'm not sure that this is the right way to do this, but this change causes the Observatory to come up correctly in the content handler.

See issue flutter/flutter#8115

Picks up changes to include inlined frames and line numbers in AOT stack traces.

Fixes https://github.com/flutter/flutter/issues/7579

In a previous change I re-included the observatory assets in the Fuchsia build, but didn't notice this bit here.

After this, if Settings::enable_observatory can be set to true somehow, the Observatory will come up in Flutter apps on Fuchsia. Unfortunately, I'm not sure how to do that.

* Document the need to sync the engine repo to avoid #8005

* Flit gclient sync and git pull

See https://github.com/flutter/flutter/issues/6807