* Add Material Study app Rally to examples

Adds the CupertinoContextMenu widget for iOS 13 support.

Fixes #42049.

git@github.com:flutter/engine.git/compare/e73c9c8f6bd5...7b968ff95ff1

git log e73c9c8f6bd5..7b968ff95ff1 --no-merges --oneline
2019-11-05 chinmaygarde@google.com Ensure that the CAMetalLayer FBO attachments can be read from. (flutter/engine#13643)
2019-11-04 47866232+chunhtai@users.noreply.github.com Revert "Added new lifecycle enum (#11913)" (flutter/engine#13632)
2019-11-04 47866232+chunhtai@users.noreply.github.com Added new lifecycle enum (flutter/engine#11913)


If this roll has caused a breakage, revert this CL and stop the roller
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git@github.com:flutter/engine.git/compare/0a8bd9dd6fbb...e73c9c8f6bd5

git log 0a8bd9dd6fbb..e73c9c8f6bd5 --no-merges --oneline
2019-11-04 skia-flutter-autoroll@skia.org Roll src/third_party/skia 8e083eee8ece..4cc2dc64ff13 (1 commits) (flutter/engine#13543)
2019-11-04 skia-flutter-autoroll@skia.org Roll fuchsia/sdk/core/mac-amd64 from ggsQ5... to XcaoM... (flutter/engine#13535)
2019-11-04 yjbanov@google.com fix getBoxesForRange for zero-length ranges (flutter/engine#13483)
2019-11-04 bkonyi@google.com Roll src/third_party/dart bbe2ac28c9..ab5cf0f854 (73 commits) (flutter/engine#13614)
2019-11-02 skia-flutter-autoroll@skia.org Roll src/third_party/skia 283ec65f632a..8e083eee8ece (32 commits) (flutter/engine#13489)
2019-11-02 skia-flutter-autoroll@skia.org Roll fuchsia/sdk/core/mac-amd64 from FKqQ_... to ggsQ5... (flutter/engine#13490)
2019-11-02 xster@google.com Release shim bindings when detaching (flutter/engine#13432)
2019-11-01 gw280@google.com Add fuchsia.intl.PropertyProvider to our services on Fuchsia (flutter/engine#13486)
2019-11-01 fmil@google.com [dart] Makes the intl services available (flutter/engine#13460)
2019-11-01 skia-flutter-autoroll@skia.org Roll fuchsia/sdk/core/linux-amd64 from 866GG... to dhwMR... (flutter/engine#13475)
2019-11-01 skia-flutter-autoroll@skia.org Roll fuchsia/sdk/core/mac-amd64 from JngMB... to FKqQ_... (flutter/engine#13477)
2019-11-01 skia-flutter-autoroll@skia.org Roll src/third_party/skia 809ec77893be..283ec65f632a (14 commits) (flutter/engine#13472)
2019-11-01 dnfield@google.com Request a reattach when creating the text input plugin on Android (flutter/engine#13474)


If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/flutter-engine-flutter-autoroll
Please CC cbracken@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
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Documentation for the AutoRoller is here:
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*Starting with arb files in lib/l10n, the tool creates the following by default:
1. An AppLocalizations class containing:
- an `AppLocalizationsDelegate`
- a `supportedLocales` property that returns a list of all supported locales.
- a `localizationsDelegate` property that returns a list containing this delegate along with `GlobalMaterialLocalizations.delegate`, `GlobalCupertinoLocalizations.delegate`, and `GlobalWidgetsLocalizations.delegate`.
2. One Dart `message_<locale>.dart` file for each arb file, as well as a `messages_all.dart` file that performs the locale message lookup. The tool infers the locale of each arb file from the @@Locale property or the arb file's name.

* Adjust and refactor all FlatButton tests into its respective file

initalValue should be initialValue

SliverAppBar - Configurable overscroll stretch with callback feature & FlexibleSpaceBar support (#42250)

* remove Source.behavior, fix bug in depfile invalidation

* more cleanup of assets

* Add skip

* address comments

* Update build_system.dart

Added tests for the new Android heading semantic flag to android_semantics_testing.

* Adding handling of TextInputClient.onConnectionClosed messages handling to Framework

* Adding more test cases for closing connection to editable_text_test

* fixing analyze error.

* Fixing analyze error in the test file

* Fixing comments on the new method

* Adding more closing connection examples.

* Indentation change

* Remove auto-add white space

* Changing the oncloseconnection behaviour to stop editing. Updating the tests

* Addressing PR comments. Added explicit log for method channnels to the tests. Added comments to the interfaces.

* add more documentation

* Wire enableFeedback parameter through MaterialButton, RawMaterialButton, and IconButton.
Co-Authored-By: Shi-Hao Hong <shihaohong@google.com>

This reverts commit 99cd4403.

This is being done to match the Material spec. It will likely break many visual diff tests.