FlatButton highlights but doesn't tap around edge

Adds support for applying forces and impulses to sprite physics

BoxConstraints.toString() should show closed intervals

Don't dump stacks when app fails to start

Now we trigger the highlight from the InkWell so that it matches the tap.

Fixes #1525

Snap to the next frame interval when visualizing stopwatch samples

Re-enable passing tests

HomogeneousViewport support for Theme.of()

Previously, RenderObjectElements didn't support being marked dirty. This
is fine, except for MixedViewport and HomogeneousViewport, which have
builder functions to which they hand themselves as a BuildContext. If
those builder functions call, e.g., Theme.of(), then when the theme
changes, the Inherited logic tries to tell the RenderObjectElement
object that its dependencies changed and that doesn't go down well.

This patch fixes this by making RenderObjectElement a BuildableElement,
and making MixedViewport and HomogeneousViewport hook into that to
rebuild themselves appropriately.

Also, this was only found at all because ThemeData didn't implement
operator==, so we were aggressively marking the entire tree dirty all
the time. That's fixed here too.

Also, I changed card_collection.dart to have more features to make this
easier to test. This found bugs #1524, #1522, #1528, #1529, #1530, #1531.

Set SkPicture tracing root directory on Android

Roll Dart runtime forward to c9334ed61f11df2d9aecc6311a5981eba0e55c01

Separate Route and PerformanceRoute

Allow updating the rasterizer tracing threshold from Dart

This patch prepares us to create routes that control their performances more
closely.

Allow capturing SKPicture traces when the rasterizer spends more than a set number of frame intervals to render a frame

Make checkbox widget to fit more closely to  material design standard…

Make checkbox widget to fit more closely to  material design standard. Make changes to remove animation artefacts.

Instead of producing a C++ stack dump when the Dart app fails to start, we just
exit with an error code.

Add markers for each frame interval while rendering statistics and scale the graph

Remove PopupMenu margin

The margins make using showMenu's menuPosition argument difficult and they're not really needed.

I also made a few small gratuitous changes in navigator.dart.

The margins make using showMenu's menuPosition argument difficult and they're not really needed.

I also made a few small gratuitous changes in navigator.dart.

NetworkImage occasionally does not grab the image

Improvements to sprite physics