Move GPU code into direct

I'll add another subdirectory to GPU for Mojo soon.

Provide a handle for the ServiceProvider stub used by the application…

Provide a handle for the ServiceProvider stub used by the application to expose services to the embedder

Update the path for dart:ui_internals

Do not delete the DrainJob within the DrainJob::Start callback

Include raw_keyboard.mojom in the Linux build too.

Nuke //ui/events, all users are runtime dead

DrainDataPipeInBackground posts a callback to DrainJob::Start, which
constructs a DataPipeDrainer.  The DataPipeDrainer's constructor may
call OnDataComplete.  If this happens, it is unsafe to delete the
DrainJob while the callback is still running.

Add a basic sky_shell.mojo

Make the user specify the path to the flutter repo in Xcode

Currently sky_shell.mojo can't load any Flutter apps or draw to the screen, but
that will come in later patches.

Move platform-specific code for sky/shell into sky/shell/platform

This patch prepares us to add support for Mozart.

The dart_pkg rule for sky_engine now preserves directory structure. Account for the same in SnapshotterInvoke

Fix sky_build.py

The dart_pkg rule for sky_engine now preserves directory structure. Account for the same in SnapshotterInvoke

Move to the service/pointer Mojo interface for input events on Mac

Move to the services/pointer Mojo interface for touch events on iOS

Hardware key support

Add the ability to dispose host objects

Some host objects hold on to a lot of state and take time to tear down. This
patch adds the ability to dispose them eagerly to release resources faster.

Switch to using callback to get observatory data (working)

Rev sky_engine and sky_services

Replace the legacy pointer input event handling with PointerPackets

With this change we no longer need engine/core/events and its IDL bindings.

Remove examples directory