Fix target name for flutter_patched_sdk so it doesn't conflict with patched_sdk target name, doesn't confuse ninja with depfile defined as .d (#3834)

* Build Flutter patched-sdk with kernel artifacts

* Switch to new dart_host_toolchain argument mechanism to let dart patch_sdk know of host_toolchain.

* Update dart dependency

* Updated licenses

* Rename dart dependencies tag so they have just 'dart_'-prefixed dart's names.

* Fix indentation and line breaks for newly added deps.

* Add toolchain for windows host

* Update dart revision

* Licenses

* Update licenses

* Revert changes to licenses_third_party

This allows the shell to be built normally for a Fuchsia host.

Fixes https://github.com/flutter/flutter/issues/9129

After this patch, we no longer link with Mojo. We still use some gn definitions
from //mojo to create Dart packages.

This change disentangles the build for the snapshotter from the main engine
build. Also, we now have all the Dart files for dart:ui in the same directory.

This patch centralizes the asset bundle processing in //flutter/assets and
removes the //base dependency from the code.

This removes most (all?) of our dependency on base::RefCountedThreadSafe.

These parts don't depend on engine anymore. Also reformat them to match Google
C++ style.

This patch moves the geometry classes.

This patch disentangles dart:jni from //sky/engine and moves it into
//flutter/lib/jni. Eventually dart:ui will move into a peer directory.

We don't use this code anymore.

Now that tonic doesn't depend on anything in //sky/engine anymore, we
can move the code to a location where its dependencies are clearer.

This matters when building for armv7 where we need the 32-bit snapshotter on the host.

This reverts commit ccd1c5ce, reversing
changes made to d4f97e4f.

This was requested by @johnmccutchan because this change broke the
analyzer, which only uses SDK version 1.14.1, since that's what we pull
in. He said he'd try again on Monday.

This patch merges these functions into dart:ui, which is simpler.

Fixes #83

Example:
  JavaClass dateFormatClass = Java.getClass('java.text.SimpleDateFormat');
  JavaObject format = dateFormatClass.newInstance('yyyy.MM.dd');
  print(format.parse('2016.01.01').getYear());

Also adopt a standard pattern for handling exceptions in JNI APIs

This also extends DartClassLibrary to support multiple DartClassProviders
for different libraries

Prior to this patch, we were still using it to generate dart_ui.dart.
We'll eventually want to reorganize the dart files in the engine. See
https://github.com/flutter/flutter/issues/1040 for some discussion.

This code was referenced by the IDL compiler, which we no longer use.

This patch removes the last IDL file from the build and unhooks the bulk
of the IDL compiler from the build system. A later patch will actually
delete the IDL compiler.

We don't use this anymore.

We don't need OpenTypeSantizer or brotli because we don't support loading fonts
over the network. Instead, fonts will need to be packaged inside the Flutter
asset bundle.