Fixes https://github.com/flutter/flutter/issues/7294

Detach the EGL surface from the GPU thread and then destroy it during the FlutterView surfaceDestroyed callback (#3316)

Fixes https://github.com/flutter/flutter/issues/7147

Fixes https://github.com/flutter/flutter/issues/7234

* This allows the tests to add their own FLX files but still use consistent fonts.
* The test fonts are only embedded on the desktop test shells. The option is not available on mobile platforms.
* Right now, all fonts will resolve to the test font. If we want tests to be able to use the fonts they embed in FLX files but use the test font for platform fallbacks, we will need to add font selector fallbacks. I can do this in an another patch. So far, there are no users of this functionality.

Now that the observatory build works in Fuchsia, use dart instead of dart_no_observatory so that dart_no_observatory can be removed from the build.

Decorate kDartWriteProtectCodeArgs with FTL_ALLOW_UNUSED_TYPE since it may not be used in all configurations. (#3302)

Fixes https://github.com/flutter/flutter/issues/7182

FlutterView's host message processing methods are invoked from native code,
and the JNI wrappers will abort the process if the Java side has an uncaught
exception.

Fixes https://github.com/flutter/flutter/issues/7174

* Test that licenses are valid.

* Move license script from flutter/buildroot to flutter/engine

SkRect objects need to be manually initialized. Previously, we were using
unintialized memory in our bounds calculations.

try 2.

* Mention updating the buildroot git remotes

I always forget how to do this...

* Update CONTRIBUTING.md

Initialize the InputConnection with the text plugin's most recent state (either incoming or outgoing) (#3283)

Fixes https://github.com/flutter/flutter/issues/7033

This allows analysis to succeed. Otherwise we're seeing errors on List which does not appear as Iterable in core/list.dart unless one has knownledge of EfficientLengthIterable which is defined in internal/internal.dart.

unzip is missing from documentation and is required to run 
"gclient sync"  successfully. Unzip does not come installed by default
on every Linux installations.
Signed-off-by: NPhilippe Ombredanne <pombredanne@nexb.com>