This patch makes three API changes:

 * The dart:ui library now always communicates in physical pixels. The
   framework is responsible for converting to whatever logical coordinate
   system it wishes to use.
 * The textBaselien property is now on TextStyle rather than ParagraphStyle,
   which will let us choose which baseline to use on a per-span basis rather
   than on a per-paragraph basis.
 * This patch also removes the old MojoServices function endpoints.

Fixes https://github.com/flutter/flutter/issues/3779
Fixes https://github.com/flutter/flutter/issues/1360

This patch teachs us how to observe tasks on Fuchsia and kick off the
microtask queue.

Have the sample build script exit after the first failed build.

* say what the engine is

closes https://github.com/flutter/flutter/issues/289

* Update README.md

Also, with the comments.

We were off by one on, uh, everything.

Fixes #5814.

(skia change 42943c8aa9c611c18ad0f1a30a27669f3d82239c)

* Added drawArc to Canvas.

Added a way to call SkCanvas::drawArc from Dart. This method is
optimized for the arc case and should be faster that drawing paths.

* Removed implementation details from docs.

* Added more details to the docs.

This patch makes it easier to share the code with
//flutter/content_handler on Fuchsia.

This removes another //base dependency and will let us reuse this code
on Fuchsia.

Add a —disable-observatory flag to explicitly disable observatory even in non-product modes. (#3012)

We used to be able to toggle observatory via a command line flag. But now, we enable or disable observatory based on the Flutter product mode.

This also allows us to fix an issue where the —non-interactive flags was being hijacked by the Dart initialization logic to enable or disable observatory. However this flag was orignally meant for the standalone runner to launch either to run tests or to run a full graphics enabled window on the desktop.

Work around a Clang issue where the compiler defines __ARM_FEATURE_CRC32 even though the crc32 instruction is unavailable. (#3010)

We can now use the real thing on Fuchsia.

This makes the code easier to share between Fuchsia and stand-alone
Flutter.

After this patch, Flutter apps on Fuchsia can access their asset
bundles. Unlike other platforms, the asset bundles are stored in memory
rather than in the file system.

This patch abstracts where the content of the zip file is stored.
Currently, zip files are stored in the file system, but in Fuchsia,
we're going to store them in memory (at least for the time being).
Rather than represent a zip file as a path in the file system, we
instead use an UnzipperProvider, which can create zip::UniqueUnzipper
objects on demand.

Pulls in fixes related to incremental builds of Dart sources that end up in the snapshotter.

* Remove references to unused GN files and flags.
* Fix Linux build.

The name of the generated packages file now includes the target name.

Rework the skia/BUILD.gn to be more disciplined about not leaking private config information to dependents. (#2996)

* Move all private config information from skia_config to skia_library_config. This was causing most skia specific defines to be applied to all targets that depended on Skia. These defines were only used by the Skia implementation. Makes the command line invocation for our sources smaller and less confusing.
* Removes defines not present in the current Skia sources.
* Dont add both directories containing SkUserConfig.h from ext and the Skia sources. Depending on the order in which the config directory was specified on the command line, the sources would use a different config.

In older versions of Skia, there were two files named SkFontMgr_fontconfig.cpp.
We want to use the one that contains SkFontMgr_FCI.  That file was renamed
to SkFontMgr_FontConfigInterface.cpp

This caused the assert in https://github.com/flutter/flutter/issues/5694

This code is unused.