* Transition to Hybrid lib/txt and blink text system.

* Revert "Enable line join styles and miter limit. (#3777)"

This reverts commit 5403f65b.

* Revert "Revert "Update switches to use StringView." (#3784)"

This reverts commit 80f039ff.

* Revert "Initial integration of libtxt with Flutter alongside Blink. (#3771)"

This reverts commit c548c65b.

* Fix pixel rounding error in the picture layer by first ensuring that
  the texture for the image is at least as big as the next integer size
  along each dimension and using kStrict_SrcRectConstraint while
  drawing the same image. We already select the source subset by
  looking at the cull rect of the picture.
* Decompose the transformation matrix into a series of operations that
  generated the same to calculate the scale at which to rasterize the
  picture. This make the rasterization scale resilient to
  transformations that introduce a perspective component to the
  resultant matrix.
* The scale in the decomposed matrix is now part of the key in the
  cache.
* Raster cache images that could never be rasterized were still taking
  part in the cache. Now, those entries are rejected early on. This
  leads to the sweep after the frame iterating over fewer items.
* Added a unit test target.

* Remove sky_snapshot sources

* update licenses

Flutter channels now also supported on iOS. Use FlutterMessageChannel or FlutterMethodChannel with binary/string/json/standard codecs.

This requires an updated buildroot.

Instead, clients should use host messaging.

* 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.

Also, teach gn how to build application bundles.

After this patch, we're able to run spinning_square on Fuchsia. I've
left some TODO comments about some shortcuts I've taken that we'll need
to improve in the future.

We're now producing a flutter_content_handler binary for Fuchsia that
builds and links.

This pulled a refactoring of how we keep track of the primary threads.

This patch removes the //flutter/sky/engine dependency from //flutter/lib/ui,
which lets us build the bulk of the dart:ui library without needing to build
//flutter/sky/engine.

Doesn't quite work yet, but close. Fuchsia is on a newer Dart and will need a
couple patches before this will fully work.

* Create an Xcode project template for dynamic service creation.

The `create_native_service_sdk.py` will be run on the buildbot similar
to `create_ios_sdk.py`. This will create an Xcode project with both arm
and x64 assets that the user can use to fill in the service
implementation.

* Add the complete_static_lib property to sdk_lib_archive in
dynamic/BUILD.gn

It is called each time the embedder initializes a Flutter view controller. The Mac shell (which does not have a view controller), calls it before NSApplicationMain.

Common items like the base::AtExitManager and the platform message loop are stored in `EmbedderState`

We now use flutter.mojo instead.

Fixes Mac builds

Android and Linux builds.

Also fixes a couple of toolchain selection issues.

Instead of using a collection of Python scripts to generate the artifacts we
want to distribute from this repository, we should just use the build system.
This CL adds a top-level |dist| target that creates these artifacts in a "dist"
directory of the build output.

Sky itself does't need to depend on //services/debugger. That's already taken
care of by //services depending on //services/debugger. Also, add some direct
depenencies from //sky/sdk to the mojom interfaces used by //sky/sdk.

TBR=eseidel@google.com

Review URL: https://codereview.chromium.org/1232783006 .

Moving sky_viewer into services/sky is more consistent with how all the other
content handlers (e.g., dart, js, nacl, pdf, python) are organized.

TBR=eseidel@google.com

Review URL: https://codereview.chromium.org/1235093002 .

This target is unused.

TBR=eseidel@google.com

Review URL: https://codereview.chromium.org/1235053003 .

R=abarth@chromium.org, abarth

Review URL: https://codereview.chromium.org/1232483002 .

This interface is growing to expose many activity-related functions, more than
just intents.

R=eseidel@chromium.org, eseidel@google.com

Review URL: https://codereview.chromium.org/1223053002 .