This change adds Dart VM event support (listening for when a VM starts/stops by using a periodic heartbeat).
This also adds support to connect to a specific `IsolateRef` through the flutter driver, so that when an application spawns, it can immediately be driven (as shown in included example code).
We're seeing occasional test timeouts trying to call `FlutterDriver.connect()`.
Unfortunately, when the test is timed out at the test runner level, you don't
get a meaningful test failure or stack trace of where the timeout occurrred.
Your test harness also doesn't get to clean up, which can include things like
saving the device logs to see what was going on in the device.
Thus, this change adds timeouts in the places where we've most
commonly observed hangs during tests.
* All lists produced by JSON parsing are List<dynamic>. If more
speficic type is required then they need to be explicitly cast, e.g.
using castFrom helper;
* Function of type (ByText) -> Finder is not a subtype of
(SerializableFinder) -> Finder because ByText is in the contravariant
position;
* In Dart 2 typed(any) should be used instead of any in mockito based
tests.
This patch reorganises flutter_driver's lib/src directory into three
subdirectories:
* driver: sources transitively imported/exported by flutter_driver.dart,
which defines the API used by driver tests executed on the host machine.
* extension: sources transitively imported/exported by
driver_extension.dart, which defines the API used to instrument a
Flutter app running on the target device for use with a driver test.
* common: sources common to both driver and extension code.
This makes rolling Flutter into repositories that use Bazel (or
Bazel-like build systems) significantly more robust, due to the simpler
glob patterns involved.
