This patch is part of a sequence of patches towards fewer top-level libraries.
In this patch, the gesture libraries are combined into one gestures.dart
library.
Also:
- don't mark a node as from the new generation if it is dirty, since we
know it still has to be built.
- establish the rule that you can't call setState() during initState()
or build().
- make syncChild() return early for unchanged children.
- update the tests, including adding a new one.
Allows a non-initialised stateful component to be used as a source of
settings more than once. Instead of asserting that it was only being
used once, we assert that once you are stateful you don't get used as a
bag of settings, which is the real thing we were trying to avoid.
A lot of code ends up using StatefulComponents as a source multiple
times in a row, and before this would fail.
Patch by Ian Hickson