Revert "Update Google Maps Plugin README. (flutter#920)"

This reverts commit 2042b10.

packages/google_maps_flutter/README.md

@@ -1,22 +1,19 @@
-# Google Maps for Flutter (Developers Preview)
+# Google Maps for Flutter
 
 [![pub package](https://img.shields.io/pub/v/google_maps_flutter.svg)](https://pub.dartlang.org/packages/google_maps_flutter)
 
-A Flutter plugin that provides a [Google Maps](https://developers.google.com/maps/) widget.
+A Flutter plugin to use [Google Maps](https://developers.google.com/maps/).
 
-## Developers Preview Status
-The plugin relies on Flutter's new mechanism for embedding Android and iOS views.
-As that mechanism is currently in a developers preview, this plugin should also be
-considered a developers preview.
-
-Known issues are tagged with the [platform-views](https://github.com/flutter/flutter/labels/a%3A%20platform-views) and/or [maps](https://github.com/flutter/flutter/labels/p%3A%20maps) labels.
-
-To use this plugin on iOS you need to opt-in for the embedded views preview by
-adding a boolean property to the app's `Info.plist` file, with the key `io.flutter.embedded_views_preview`
-and the value `YES`.
-
-The API exposed by this plugin is not yet stable, and we expect some breaking changes to land soon.
+## Caveat
 
+This plugin provides an *unpublished preview* of the Flutter API for Google Maps:
+* Dart APIs for controlling and interacting with a GoogleMap view from Flutter
+  code are still being consolidated and expanded. The intention is to grow
+  current coverage into a complete offering. Issues and pull requests aimed to
+  help us prioritize and speed up this effort are very welcome.
+* Currently the plugin only supports Android as it embeds a platform view in the
+  Flutter hierarchy which is currently only supported for Android ([tracking
+  issue](https://github.com/flutter/flutter/issues/19030)).
 
 ## Usage
 
@@ -33,8 +30,6 @@ as a [dependency in your pubspec.yaml file](https://flutter.io/platform-plugins/
 
 Get an API key at <https://cloud.google.com/maps-platform/>.
 
-### Android
-
 Specify your API key in the application manifest `android/app/src/main/AndroidManifest.xml`:
 
 ```xml
@@ -44,32 +39,6 @@ Specify your API key in the application manifest `android/app/src/main/AndroidMa
                android:value="YOUR KEY HERE"/>
 ```
 
-### iOS
-
-Specify your API key in the application delegate `ios/Runner/AppDelegate.m`:
-
-```objectivec
-#include "AppDelegate.h"
-#include "GeneratedPluginRegistrant.h"
-#import "GoogleMaps/GoogleMaps.h"
-
-@implementation AppDelegate
-
-- (BOOL)application:(UIApplication *)application
-    didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
-  [GMSServices provideAPIKey:@"YOUR KEY HERE"];
-  [GeneratedPluginRegistrant registerWithRegistry:self];
-  return [super application:application didFinishLaunchingWithOptions:launchOptions];
-}
-@end
-```
-
-Opt-in to the embedded views preview by adding a boolean property to the app's `Info.plist` file
-with the key `io.flutter.embedded_views_preview` and the value `YES`.
-
-### Both
-
-
 You can now add a `GoogleMap` widget to your widget tree.
 
 The map view can be controlled with the `GoogleMapController` that is passed to