Merge in the flutter gallery (#176)

gallery/README.md

@@ -0,0 +1,30 @@
+# Flutter Gallery
+
+Flutter Gallery is a resource to help developers evaluate and use Flutter.
+It is a collection of material design widgets, behaviors, and vignettes
+implemented with Flutter. We often get asked how one can see Flutter in
+action, and this gallery demonstrates what Flutter provides and how it
+behaves in the wild.
+
+## Supported Platforms
+
+The Flutter Gallery application has been built to support multiple platforms. This includes:
+
+* Android
+* iOS
+* web
+* macOS
+* Linux
+* Windows
+
+That being said, extra steps must be taken to [enable Desktop support](https://github.com/flutter/flutter/wiki/Desktop-shells#tooling).
+
+Additionally, the UI adapts between mobile and desktop layouts regardless of the platform it runs on. This is determined based on window size as outlined in [adaptive.dart](https://github.com/material-components/material-components-flutter-gallery/blob/master/gallery/lib/layout/adaptive.dart).
+
+## To include a new splash animation
+
+1. Convert your animation to a `.gif` file. Ideally, use a background color of `0xFF030303` to ensure the animation blends into the background of the app.
+
+2. Add your new `.gif` file to the assets directory under `assets/splash_effects`. Ensure the name follows the format `splash_effect_$num.gif`. The number should be the next number after the current largest number in the repository.
+
+3. Update the map `_effectDurations` in [splash.dart](https://github.com/material-components/material-components-flutter-gallery/blob/master/gallery/lib/pages/splash.dart) to include the number of the new `.gif` as well as its estimated duration. The duration is used to determine how long to display the splash animation at launch.