Also fill in some related dartdocs.

Now past halfway though material.dart by files.

Roll engine to c3504b519fcd95179ea832460758712ecd0e433d

This picks up a change which fixes deps files generated by the snapshotter.

* ClampOverscrolls Inherited Widget

* add a --deploy flag to build apk

* update command description

* use an enum instead of a bool param for build variants

* rename buildForDeploy flag to buildVariant

* review comments

Migrate `enable-strict-call-checks` flag to options file.

As per https://github.com/dart-lang/sdk/issues/25723, moves last command-line flag to `.analysis_options`.

Analyze Command lint cleanup.

The push to dev-4 allows us to cleanup a few more bits:
  * `api_docs` lint message special casing (lint fixed)
  * `allowedIdentifiersPattern` (lint fixed)

* more terse flutter upgrade

* fix an issue when updating and the engine update code has changed

* call flutter precache; add a --no-color hidden option

* fix a lint related to getters/setters

I ran into a case where I was setting minHeight=∞ and then calling
layout() with that constraint, which is all kinds of bad. To try to
catch this earlier, this patch now provides a way to catch constraints
that are requiring infinite values.

We don't _always_ check this because there are valid uses for
BoxConstraints.biggest, e.g. as an additionalConstraint.

* better messaging about windows support

* fix lints

* Add validity checks to create

* Adjust indent

* Remove ScrollableListPainter

* Added OverscrollIndicator, removed OverscrollIndicatorPainter

* add a target for android-x64

* update armeabi-v7a to x86_64

We need to listen to the Scaffold's animation so that we rebuild every time it
ticks so that we can drive our animations.

Fixes #3197

The dartdoc will continue until morale improves.

These columns were secretly re-creating Block in a more complex way. Now we
just use Block directly.

Also, update hello_android to use the new Java class names.

* have flutter precache print if there's no work to do

* tweak precache

We need to pin the version of package:analyzer we use to avoid version skew
within our project.

Do not check for an existing package map if a command is going to run "pub get" to update the package map (#3202)

Also remove a redundant check for the --pub option in the run command

This command explicitly populates the flutter tool's cache of binary artifacts.
Also, teach `flutter create` to update the cache in case its the first command
that a user runs.