### Context
As the team pivots to using theming within extensions we have started off with buttons as a test run. This will be part fo the work with buttons only addressing the contained button type. This adds a new method to MDCButton - `applyContainedThemeWithScheme:(id<MDCContainerScheming>)scheme`
### The problem
We currently do not theme buttons the way the team has decided to theme them
### The fix
This themes Contained buttons with the new style we have all agreed on.
### Remaining Work
Theming for Text and Outlined buttons in this new style.
{MDC iOS} No longer using `-init` for Color Scheme.
Based on the discussions in go/mdc-ios-theming, we should not use the `-init` default initializer. Instead, we should use an explicit set of defaults.
Search regex: '\[\[MDCSemanticColorScheme alloc\] init\]'
Replacing all non-integral, single-precision floating point literals with double-precision values explicitly cast to CGFloat. For example, `0.1f` should become `(CGFloat)0.1`.
Regex used:
```
([0-9]*\.)([0-9]*?)([1-9]+)([0-9]*?)[fF]
```
PiperOrigin-RevId: 220683126
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.
```
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
Pivotal Story: https://www.pivotaltracker.com/story/show/156168281
* Implementation of Shapes support in Buttons.
* Added example of using shapes on different styles of buttons (see screenshot and gif below).
* Exposed an initializer for MDCCurvedCornerTreatment to be able to use in the example.
* Exposed the color sublayer in MDCShapedShadowLayer to allow hierarchal reordering of sublayers for a shaped button to work with ink and shadow correctly.
* Updated unit tests.
