Remove public accessor for paint dirty state

If we use null for these values, the implementations will later assert.



Fixes #3102

This picks up a change which causes ChildViews to jank instead of flicker during resize.

Fixes https://github.com/flutter/flutter/issues/2713

This will let us draw in-row bottom borders and row-wide backgrounds,

both of which are necessary for Material data tables.

Using .of() to call mutating setters is not great practice since it ties

parts of the app together in ways that prevent reuse and composition.



Since people are now using the gallery app to copy from, let's use the

better practice of using callbacks.

Gallery Tweaks

Specifically, explain how to create both determinate and indeterminate progress

indicators.



Fixes #3055

* Enable the lint require documentation.

* Track how many public Flutter members lack docs

* Rename the .analysis_options file

This makes Atom happier in the flutter_tools package.

Fixes #1541

- Create a FlutterErrorDetails struct-like class that describes an

  exception along with more details that aren't in the exception, like

  where it was caught and what was going on when it was caught.



- Provide a FlutterError static API for handling these objects:



  - FlutterError.onError which is called whenever Flutter catches an

    error.



  - FlutterError.reportError() which handles an error.



  - FlutterError.dumpErrorToConsole() which is the default behavior

    for onError.



- Removes all the existing exception handler callbacks.



- Replaces all the existing places that described exceptions using

  debugPrint with calls to FlutterError.reportError().



- Extend lockState() to also catch exceptions, so that we catch

  exceptions that happen during finalizers.



- Make the test framework catch errors and treat them as failures.



- Provide a mechanism to override this behavior in the test framework.



- Make the tests that used to depend on the exception handler

  callbacks use this new mechanism.



- Make pump() also support the phase argument.



- Improve some tests using these new features.



Fixes #2356, #2988, #2985, #2220.

For example, to implement backdrop blur effects.

[driver] utility for extracting and saving timeline summary

This way, widgets that try to use the DefaultTextStyle don't have to

handle the case where there isn't an explicit default.

Turns out card_collection had all kinds of bugs.

Initial version of complex layout performance test

Tweak the typography demo to match the spec more

Previously we weren't padding the top and the bottom of drop-down menus but the

spec says these should have 8.0 pixel of padding, the same as popup menus.



Fixes #2683

Support "flutter refresh" in the Gradle-based sample project

* sort imports

Polish selection controls

Leave all entered targets when finishing.

pubspec normalization; remove den

Capture closures around megamorphic dispatches

The performLayout and build callsite are highly megamorphic because they
dispatch into a large number of clients. However, for a given caller, the
callee is always of the same type, which means the megamorphic lookup exactly
factors by the caller. We can speed up the dispatch by capturing a closure at
initialization and then monomorphically dispatching through the closure.

Add a scrolling test now that it passes

Update engine version

Don't delay between dismissing a snack bar and the next snack bar