Fix some Iterable comments.

sdk/lib/async/stream.dart

Index: sdk/lib/async/stream.dart
diff --git a/sdk/lib/async/stream.dart b/sdk/lib/async/stream.dart
index 95835e3fe6316255fb7d3635e47633ca3fc24354..4be59b7326b09d1f0706db8ddf935b85f13c1097 100644
--- a/sdk/lib/async/stream.dart
+++ b/sdk/lib/async/stream.dart
@@ -519,7 +519,7 @@ abstract class Stream<T> {
    * when either this stream is done, or when this stream first provides
    * a value that [test] doesn't accept.
    */
-  Stream<T> takeWhile(bool test(T value)) {
+  Stream<T> takeWhile(bool test(T element)) {
     return new _TakeWhileStream(this, test);
   }
 
@@ -538,7 +538,7 @@ abstract class Stream<T> {
    * Starting with the first data event where [test] returns true for the
    * event data, the returned stream will have the same events as this stream.
    */
-  Stream<T> skipWhile(bool test(T value)) {
+  Stream<T> skipWhile(bool test(T element)) {
     return new _SkipWhileStream(this, test);
   }
 
@@ -659,7 +659,7 @@ abstract class Stream<T> {
    * with no [defaultValue] function provided, the future will receive an
    * error.
    */
-  Future<T> firstWhere(bool test(T value), {T defaultValue()}) {
+  Future<T> firstWhere(bool test(T element), {T defaultValue()}) {
     _FutureImpl<T> future = new _FutureImpl<T>();
     StreamSubscription subscription;
     subscription = this.listen(
@@ -696,7 +696,7 @@ abstract class Stream<T> {
    * That means that the result cannot be provided before this stream
    * is done.
    */
-  Future<T> lastWhere(bool test(T value), {T defaultValue()}) {
+  Future<T> lastWhere(bool test(T element), {T defaultValue()}) {
     _FutureImpl<T> future = new _FutureImpl<T>();
     T result = null;
     bool foundResult = false;
@@ -738,7 +738,7 @@ abstract class Stream<T> {
    * Like [lastMatch], except that it is an error if more than one
    * matching element occurs in the stream.
    */
-  Future<T> singleWhere(bool test(T value)) {
+  Future<T> singleWhere(bool test(T element)) {
     _FutureImpl<T> future = new _FutureImpl<T>();
     T result = null;
     bool foundResult = false;