Currently we're automatically registering plugins both when the
FlutterEngine is constructed and in the `flutter create` template, when
FlutterActivity#configureFlutterEngine is called. The initial
registration is too early to contain a reference to the activity and the
second registration can cause problems in some plugins.

This alters the flow so automatic registration happens in two discrete
places, and contains the `activity` in its first and only call for most
apps.

1. We're no longer automatically registering plugins on `FlutterEngine`
in any of our activities/fragments at construction time. But since the
FlutterEngine default constructor still automatically registers plugins,
anyone constructing the engine themselves (for example, in a service) is
still going to get automatic registration at `FlutterEngine`
instantiation time.
2. We now automatically register plugins in the base `FlutterActivity`'s
`configureFlutterEngine` hook. Anyone using `FlutterActivity` (or
`FlutterFragment`) should be automatically registered once that hook is
called. Right now the `flutter create` template overrides the base class
method with a subclass that registers everything manually in the same
spot. But with this in place we can safely recommend to remove the
subclass and rely on this hook to automatically register going forward.
Registering at this time means `activity` is set correctly.

Roll fuchsia/sdk/core/mac-amd64 from 7fqYj... to 35pbn...

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/fuchsia-mac-sdk-flutter-engine
Please CC  on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Eliminates an unused dependency on android.os.build. The last remaining
use of this was eliminated in 0615f456
with the removal of an unused method that contained an android version
check.

* Calling platform message callback after copy

* addressing pr comments

* adding unit tests to clipbpard.dart

fixes https://github.com/flutter/flutter/issues/47178

This paves the way for us to have shell_unittests backed by different rendering APIs (e.g. OpenGL, Vulkan, Metal).

https://github.com/flutter/flutter/issues/49132

Roll fuchsia/sdk/core/mac-amd64 from 6_pZp... to 7fqYj...

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/fuchsia-mac-sdk-flutter-engine
Please CC  on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

https://dart.googlesource.com/sdk.git/+log/bc9348829ef8..fc3af737c759

git log bc9348829ef8..fc3af737c759 --date=short --first-parent --format='%ad %ae %s'
2020-01-24 lrn@google.com Update typed-data constructor documentation.
2020-01-24 cskau@google.com [SDK] Fixes async* stack unwinding.

Created with:
  gclient setdep -r src/third_party/dart@fc3af737c759

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dart-sdk-flutter-engine
Please CC dart-vm-team@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Bug: None
Tbr: dart-vm-team@google.com

https://skia.googlesource.com/skia.git/+log/a7e557f3e353..3ea4d5bb857d

git log a7e557f3e353..3ea4d5bb857d --date=short --first-parent --format='%ad %ae %s'
2020-01-24 skia-autoroll@skia-public.iam.gserviceaccount.com Roll ../src 7afe38da7578..2ae619822948 (463 commits)
2020-01-24 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/angle2 135f8fcba837..f3b4e6c3030f (8 commits)
2020-01-24 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader f324fe10ca65..5ef91b82cbed (6 commits)
2020-01-24 bsalomon@google.com Add support for GL_NV_fence.

Created with:
  gclient setdep -r src/third_party/skia@3ea4d5bb857d

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/skia-flutter-autoroll
Please CC benjaminwagner@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Bug: None
Tbr: benjaminwagner@google.com

https://dart.googlesource.com/sdk.git/+log/c359b5943a52..bc9348829ef8

git log c359b5943a52..bc9348829ef8 --date=short --first-parent --format='%ad %ae %s'
2020-01-24 srawlins@google.com NNBD preview: change the Edit Details response to be JSON

Created with:
  gclient setdep -r src/third_party/dart@bc9348829ef8

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dart-sdk-flutter-engine
Please CC dart-vm-team@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Bug: None
Tbr: dart-vm-team@google.com

https://dart.googlesource.com/sdk.git/+log/3eaae5405d37..c359b5943a52

git log 3eaae5405d37..c359b5943a52 --date=short --first-parent --format='%ad %ae %s'
2020-01-24 rmacnak@google.com [vm, service] Fix and enable more services tests.
2020-01-24 scheglov@google.com Convert opt-in elements to legacy when resolving annotations.
2020-01-24 bkonyi@google.com [ dartfuzz ] Fixed type table for `sumManyDoubles`
2020-01-24 bkonyi@google.com Revert "[vm] resolve symbolic link to find kernel_service snapshot"
2020-01-24 brianwilkerson@google.com Remove the notion of required fixes from dartfix and the server
2020-01-23 pquitslund@google.com de-dup mutiply exported elements
2020-01-23 jakemac@google.com Allow http uris in frontend_server, front_end, and ddc.
2020-01-23 asiva@google.com [VM/libraries] Address code review comment from previous CL.
2020-01-23 scheglov@google.com Fixes for NORM and FunctionType(s) - type parameters, and covariant formal parameters.
2020-01-23 zichangguo@google.com [vm] resolve symbolic link to find kernel_service snapshot
2020-01-23 rmacnak@google.com [vm, service] Fix race in Service.controlWebServer / getInfo.
2020-01-23 srawlins@google.com NNBD preview: Make navigation directories collapsible; closes #40109
2020-01-23 asiva@google.com [VM/libraries] Fix more analyzer warnings related to NNBD in patch files.

Created with:
  gclient setdep -r src/third_party/dart@c359b5943a52

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dart-sdk-flutter-engine
Please CC dart-vm-team@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Bug: None
Tbr: dart-vm-team@google.com

https://skia.googlesource.com/skia.git/+log/c88a3bc3f561..a7e557f3e353

git log c88a3bc3f561..a7e557f3e353 --date=short --first-parent --format='%ad %ae %s'
2020-01-24 michaelludwig@google.com Reland "Increase precision of some quad AA calculations"
2020-01-24 recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com Roll recipe dependencies (trivial).
2020-01-23 reed@google.com remove legacy SkMScalar code
2020-01-23 mtklein@google.com use longer-lived alloc in CacheKey()
2020-01-23 mtklein@google.com force skvm interpreter in ASAN builds, add bots
2020-01-23 brianosman@google.com Use PipelineStageArgs throughout GrSkSLFP and PipelineStageCodeGenerator

Created with:
  gclient setdep -r src/third_party/skia@a7e557f3e353

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/skia-flutter-autoroll
Please CC benjaminwagner@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Bug: None
Tbr: benjaminwagner@google.com

Roll fuchsia/sdk/core/mac-amd64 from LAOYs... to 6_pZp...

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/fuchsia-mac-sdk-flutter-engine
Please CC  on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

See: flutter/flutter#46750

Some objc objects are not released in the iOS embedder. This fixes a
subset of those leaks in FlutterPlatformPlugin.mm.

See https://github.com/flutter/flutter/issues/49358

This class is meant to be thread safe. In fact, its headerdoc statement on
thread safety even mentions this. All fields on the class are readonly except
the child isolate preparer. This field is set during VM instantiated isolate
initialization. The VM may launch multiple isolate in the same isolate group on
at the same time (each on a VM backed thread pool thread). Attempting to set the
field without synchronization is a data race.

Fixes https://github.com/flutter/flutter/issues/49358
Fixes b/147798920

Calling Dart_TimelineEvent has a performance cost, and the APIs for collecting
timeline events are not available in release mode.

https://dart.googlesource.com/sdk.git/+log/e84bea25df23..3eaae5405d37

git log e84bea25df23..3eaae5405d37 --date=short --first-parent --format='%ad %ae %s'
2020-01-23 nbosch@google.com Enable and fix directives_ordering lint
2020-01-23 jakemac@google.com Remove multiRootOutputPath special case for package: uris
2020-01-23 aam@google.com [io/file_watching] Skip unwatching if listener has been closed already.
2020-01-23 asiva@google.com Update ABI version.
2020-01-23 nshahan@google.com [dartdevc] Update FutureOr is, as, and _check methods for NNBD
2020-01-23 paulberry@google.com Migration: Fix hang in preview server when an exception occurs.
2020-01-23 paulberry@google.com Migration: as a temporary measure, remove code via commenting it out.
2020-01-23 scheglov@google.com Revert "Use NNBD_TOP_MERGE to combine signatures of the inherited members."
2020-01-23 mfairhurst@google.com [nnbd_migration] Don't union implicit types to bounds
2020-01-23 jcollins@google.com Updates to steamroll_ecosystem prior to port.
2020-01-23 rmacnak@google.com [test] Update copied mirrors tests for Dart 3.
2020-01-23 rmacnak@google.com [test] Run some service tests in AOT.
2020-01-23 scheglov@google.com Use NNBD_TOP_MERGE to combine signatures of the inherited members.
2020-01-23 brianwilkerson@google.com Update a preview site after adding or removing a hint
2020-01-23 paulberry@google.com Migration: switch to using the FixBuilder.
2020-01-23 dmitryas@google.com [cfe] Report errors on missing default values of optional parameters
2020-01-23 vsm@google.com [dartdevc/nnbd] run co19 tests

Created with:
  gclient setdep -r src/third_party/dart@3eaae5405d37

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dart-sdk-flutter-engine
Please CC dart-vm-team@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Bug: None
Tbr: dart-vm-team@google.com

https://skia.googlesource.com/skia.git/+log/e4ddb8a7cddc..c88a3bc3f561

git log e4ddb8a7cddc..c88a3bc3f561 --date=short --first-parent --format='%ad %ae %s'
2020-01-23 jlavrova@google.com Bidi segmentation BEFORE anything else
2020-01-23 csmartdalton@google.com Move GrTessellator::VertexAllocator to GrEagerVertexAllocator
2020-01-23 herb@google.com Convert evict callback from function to interface
2020-01-23 brianosman@google.com Remove unused functions and members from PipelineStageCodeGenerator
2020-01-23 mtklein@google.com more bits for shader program hash
2020-01-23 recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com Roll recipe dependencies (trivial).
2020-01-23 robertphillips@google.com Clean up some "const SkISize& dimensions" usages w/in Ganesh
2020-01-23 reed@google.com Don't make promises about rowbytes
2020-01-23 egdaniel@google.com Treat GrTextureAdjusters mip copy like other producers, i.e. no fallback.
2020-01-23 michaelludwig@google.com Revert "Increase precision of some quad AA calculations"
2020-01-23 mtklein@google.com basic pass at gradients
2020-01-23 reed@google.com remove some memory-based methods, add rc()
2020-01-23 senorblanco@chromium.org Implement support for framebufferOnly render targets.
2020-01-23 egdaniel@google.com GrPixelConfig is DEAD!!!!!
2020-01-23 halcanary@google.com Fix build when (is_ios && !skia_enable_skottie)
2020-01-23 michaelludwig@google.com Increase precision in barycentric_coord calculations
2020-01-23 egdaniel@google.com Remove fConfig from GrSurfaceDesc.
2020-01-23 bsalomon@google.com Fix issue introduced in 33c0f260d28e28dbb5e34be71ffcbd5165a83bb3
2020-01-23 michaelludwig@google.com Increase precision of some quad AA calculations
2020-01-23 herb@google.com Reland "Specialize SkRectanzier to SkRectanizerSkyline"
2020-01-23 reed@google.com row/col methods
2020-01-23 reed@google.com remove obsolete flag SK_SUPPORT_LEGACY_CANVAS_MATRIX_VIRTUALS
2020-01-23 brianosman@google.com Disable Programs test on MacBook10.1-Metal
2020-01-23 michaelludwig@google.com Add GM for crbug:10141204

Created with:
  gclient setdep -r src/third_party/skia@c88a3bc3f561

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/skia-flutter-autoroll
Please CC benjaminwagner@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Bug: None
Tbr: benjaminwagner@google.com

This is to address fxb/44063

In all the other modes they will be sent to the systrace