flutter_tools testing requires the FLUTTER_TOOLS environment variable to
be set.

* Add note about ensuring that no devices are connected

- MaterialList
 - ScrollableList
 - ScrollableLazyList
 - LazyBlock

All of these widgets can be replaced by ListView now.

The new scrolling machinery doesn't support snap scrolling.

Also fixes a bug when trying to update the offset of a viewport in a layout
builder.

Fixes #8054

For measuring the Dart thread, we care about thread duration (tdur) rather than
wall duration (dur) because we don't want to count the time when the Dart
thread is descheduled (e.g., in preference to the raster thread).

Prior to this change, these benchmarks were mostly measuring whether the OS
decided to finish the Dart thread's time slice or hand over the CPU to the
raster thread to complete the visual part of the frame. Now we actually measure
the work done on the Dart thread.

I've been using these locally, but they're likely to be useful to other people
as well.

When a ListView scrolls, it generates a LayoutChangedNotification, which was
causing Material to repaint unconditionally. That's not necessary if there are
no ink effects that need to be moved. This patch skips the repaint in that
case.

Fixes #7937

Fixes: #8087.

* move flutter user analysis options file
* add comments referencing each of the analysis options files

The old release contained some unused files that caused trouble on the Windows Chromebot.

* Add platform_services sample

* update build.gradle to use latest scripts

* use FlutterActivity

* Updated ExampleInstrumentedTest.java and deleted FlutterPlugin.groovy

* Remove getRandom code from main.dart

* remove unused import

Previously the "left" padding was applied on the right when hit testing
a reversed vertical list view.

This test was a bit tricky to convert because it subtly relied upon the
lazy evaluation of an Iterable.

The onDismissed from Dismissable happens during the animation phase of
the pipeline. Previously, the ScrollableList had already been built for
that frame but had not evaluated its Iterable yet. When we got to the
layout phase, ScrollableList evaluated its Iterable and saw the updated
version of dismissedItems.

A straightforward conversion to ListView calls toList() when building
the ListView, but that evaluates the iterable when buildTest() is
called, which is before the calls to pump and therefore before the
animation phase, meaning the Iterable sees the old value of
dismissedItems.

This patch fixes the test to use the normal setState pattern to signal
that state upon which the build depends has changed. Now, the
onDismissed callback happens during the animation phase and the
StatefulBuilder is marked as dirty via setState, which causes it to
rebuild the ListView and re-evaluate the Iterable, seeing the updated
version of dismissedItems.

This change also lets us replace the gratuious use of pumpWidget with
pump now that we use setState rather than pumpWidget to trigger a
rebuild.

Clients should use ListView instead.

We've decided not to store the scroll position in PageStorage because
routes now maintainState by default.

Fixes #8051

The last remaining client is complex_layout.

They previously were very sensitive to widgets like LayoutBuilder.

These now test ScrollNotification2.

Replace version-specific link with a version-independent URL.

See https://github.com/flutter/flutter/issues/7579

This used to be the logic before I made the tests portable.

Fixes https://github.com/flutter/flutter/issues/7974

* Make new project template gradle-based for Android.

With this change, the 'new project' template uses the same gradle-based build for Android as the hello_services example. This has some implications on build performance, since we're now building a complete Android app instead of just combining a pre-compiled .dex with the Flutter assets.

The very first build is a little over 2x slower, since it needs to download gradle and build the build scripts before getting to the actual code. Subsequent builds with changes to the code are comparable to the old builds. Null builds are faster. Enabling the gradle daemon speeds up subsequent builds by around 5s.

* Move Flutter Gradle plugin to Flutter root.

Having the drawer docs lead with "this is a drawer" wasn't very
helpful when scanning.

qv. study P6.

Fixes https://github.com/flutter/flutter/issues/7963