Now they all flow through some common routines.

Now we just pass the data directly.

Previously, these signals were sent over Mojo. Now we send them through
platform messages.

Instead, just use JNI and Objective-C directly.

We no longer offer mojo handles via this mechanism.

This patch removes the use of the host messages mojom and switch all
message routing over to platform messages.

This plugin is implemented internally by the engine to integrate with the asset
system.

Previously we had a mix of the two.

Add plunbing for Host-to-Dart platform messages

We'll use the plumbing in this direction for things like key events.

After this patch, platform messages now take the same path through the system
that semantics data does (on Android). Support on iOS will be in another patch.

TalkBack still isn't fully working, but this patch gets us much closer.

This fixes this Fuchsia build, which uses the latest //lib/ftl.

This transport uses the Dart and JNI APIs directly instead of indirecting
through Mojo.

We only ever had one UIDelegate. We might as well have people use the Engine
interface directly.

This patch moves the rest of the clients to use the new PointerData
transport.

This patch prepares us to switch sending semantics information over mojom to
using dart:ui directly. Currently the recorded information is dropped on the
floor, but that will improve in future patches.

We now use JNI rather than Mojo to transport pointer data from Java to Dart.
Also, fill in a few more of the pointer data fields from information in Java.

This is intended for use in flutter_driver tests

Long live pointer data packets.

Rather than using mojom to encode pointer data, we now encode and decode it
manually. A future patch will remove the mojom codepath once the framework is
updated.

If the platform requests setting up the resource context without making the context current, don’t attempt to create the GL native interface. (#3059)

* Namespaces have been updated to reflect the move from //flutter/sky/shell to //flutter/shell.
* shell/BUILD.gn file has been split into smaller GN files for each subcomponent of the shell (common, GPU, diagnostic, testing).
* GN dependencies have been rewritten to stop exposing common shell dependencies as public. Duplicates have also been removed.
* GPU subcomponent has been updated make it more suitable for Vulkan integration.
* The GLFW backend has been resurrected.