update changelog for recent strong mode fixes to future

CHANGELOG.md

 ## 1.19.0
 
 ### Language changes
 
 * The language now allows a trailing comma after the last argument of a call and
  the last parameter of a function declaration. This can make long argument or
  parameter lists easier to maintain, as commas can be left as-is when
  reordering lines. For details, see SDK issue
  [26644](https://github.com/dart-lang/sdk/issues/26644).
 
@@ skipping 12 matching lines @@
     see the [documentation](https://github.com/dart-lang/dev_compiler/blob/master/doc/STATIC_SAFETY.md#disable-implicit-casts)
     for usage instructions and examples.
 
 *   New feature - an option to disable implicit dynamic
     (SDK issue [25573](https://github.com/dart-lang/sdk/issues/25573)),
     see the [documentation](https://github.com/dart-lang/dev_compiler/blob/master/doc/STATIC_SAFETY.md#disable-implicit-dynamic)
     for usage instructions and examples.
 
 *   Breaking change - infer generic type arguments from the
     constructor invocation arguments
-    (SDK issue [25220](https://github.com/dart-lang/sdk/issues/25220))
+    (SDK issue [25220](https://github.com/dart-lang/sdk/issues/25220)).
 
     ```dart
     var map = new Map<String, String>();
 
     // infer: Map<String, String>
     var otherMap = new Map.from(map);
     ```
 
 *   Breaking change - infer local function return type
-    (SDK issue [26414](https://github.com/dart-lang/sdk/issues/26414))
+    (SDK issue [26414](https://github.com/dart-lang/sdk/issues/26414)).
 
     ```dart
     void main() {
       // infer: return type is int
       f() { return 40; }
       int y = f() + 2; // type checks
       print(y);
     }
     ```
 
 *   Breaking change - allow type promotion from a generic type parameter
-    (SDK issue [26414](https://github.com/dart-lang/sdk/issues/26965))
+    (SDK issue [26414](https://github.com/dart-lang/sdk/issues/26965)).
 
     ```dart
     void fn/*<T>*/(/*=T*/ object) {
       if (object is String) {
         // Treat `object` as `String` inside this block.
         // But it will require a cast to pass it to something that expects `T`.
         print(object.substring(1));
       }
     }
     ```
 
+* Breaking change - smarter inference for Future.then
+    (SDK issue [25944](https://github.com/dart-lang/sdk/issues/25944)).
+    Previous workarounds that use async/await or `.then/*<Future<SomeType>>*/`
+    should no longer be necessary.
+
+    ```dart
+    // This will now infer correctly.
+    Future<List<int>> t2 = f.then((_) => [3]);
+    // This infers too.
+    Future<int> t2 = f.then((_) => new Future.value(42));
+    ```
+
+* Breaking change - smarter inference for async functions
+    (SDK issue [25322](https://github.com/dart-lang/sdk/issues/25322)).
+
+    ```dart
+    void test() async {
+      List<int> x = await [4]; // was previously inferred
+      List<int> y = await new Future.value([4]); // now inferred too
+    }
+    ```
+
 ### Dart VM
 
 *   The dependency on BoringSSL has been rolled forward. Going forward, builds
     of the Dart VM including secure sockets will require a compiler with C++11
     support, and to link against glibc 2.16 or newer. For details, see the
     [Building wiki page](https://github.com/dart-lang/sdk/wiki/Building).
 
 ### Tool Changes
 
 * `dartfmt` - upgraded to v0.2.9
@@ skipping 1087 matching lines @@
     they will keep the Dart process alive until they time out. This fixes the
     handling of persistent connections. Previously, the client would shut down
     immediately after a request.
 
   * **Breaking change:** `HttpServer` no longer compresses all traffic by
     default. The new `autoCompress` property can be set to `true` to re-enable
     compression.
 
 * `dart:isolate`: `Isolate.spawnUri` added the optional `packageRoot` argument,
   which controls how it resolves `package:` URIs.