Add a will present block to the MDCSnackbarMessage class. This allows for clients who wish to customize their snackbar message view (MDCSnackbarMessageView) instance, but without exposing UI properties on the message objects. This also makes it easier for clients who have multiple files where they show the snackbar with only one Manager to not have issues with different classes stealing the MDCSnackbarDelegate in order to add customization to the snackbar view.
This new API when set to YES allows the Snackbar to be focused and stay on screen by issuing a UIAccessibilityLayoutChangedNotification on the snackbar message view.
When the Scheme is nil, the Snackbar gets weird colors and is presented wrong. Because Dragons doesn't receive a scheme, we need to explicitly create a scheme in each of the examples to fix the color for Snackbars.
Removes the need to copy-paste stanzas from other files anymore as we'll rely on #4478 to generate the correct stanza for us instead.
This was an automated change generated by running a find-and-replace regular expression:
```
/\*
Copyright ([0-9]+)-present the Material Components for iOS authors\. All Rights Reserved\.
Licensed under the Apache License, Version 2\.0 \(the "License"\);
you may not use this file except in compliance with the License\.
You may obtain a copy of the License at
http://www\.apache\.org/licenses/LICENSE-2\.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied\.
See the License for the specific language governing permissions and
limitations under the License\.
\*/
```
```
/\*
Copyright ([0-9]+)-present the Material Components for iOS authors\. All Rights Reserved\.
Licensed under the Apache License, Version 2\.0 \(the "License"\);
you may not use this file except in compliance with the License\.
You may obtain a copy of the License at
http://www\.apache\.org/licenses/LICENSE-2\.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied\.
See the License for the specific language governing permissions and
limitations under the License\.
\*/
```
```
/\*
Copyright ([0-9]+)-present the Material Components for iOS authors\. All Rights Reserved\.
Licensed under the Apache License, Version 2\.0 \(the "License"\);
you may not use this file except in compliance with the License\.
You may obtain a copy of the License at
http://www\.apache\.org/licenses/LICENSE-2\.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied\.
See the License for the specific language governing permissions and
limitations under the License\.
\*/
```
```
// Copyright $1-present the Material Components for iOS authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
```
Users of Switch Control could not access the cells needed to make Snackbars
appear. For VoiceOver, the accessibilityLabel, accessibilityValue, and
accessibilityHint for the cells in the Message Suspension example were not
integrated with the cells themselves.
Closes#4712
Made colorScheme and typographyScheme properties in the class interfaces for all our examples.
Moved theming away from example inits and into viewDidLoad
Small update for slider example to allow it to grab the theming properly.
Related Pivotal: https://www.pivotaltracker.com/story/show/156616695
* Reset bottomOffset when leaving example
* Expand snackbar to cover safeAreaInsets
* Review fixes
* Take horizontal safeAreaInsets in to account
* Review Fix#2
All examples now have at least the required `+catalogBreadcrumbs` and `+catalogIsPrimaryDemo`. All examples in the same breadcrumbs path have only one primary demo. There should be only one `-catalogDescription` attached to the primary demo.
Closes#1897
