Let operator* in Duration accept doubles.

sdk/lib/core/duration.dart

Index: sdk/lib/core/duration.dart
diff --git a/sdk/lib/core/duration.dart b/sdk/lib/core/duration.dart
index a0cf1b601b64238d20732a84d79b2e1aa9d1f188..5d56e19b6977ad35b94c7fcc0e3dfd2fc3f1f859 100644
--- a/sdk/lib/core/duration.dart
+++ b/sdk/lib/core/duration.dart
@@ -56,7 +56,7 @@ class Duration implements Comparable<Duration> {
                   int minutes: 0,
                   int seconds: 0,
                   int milliseconds: 0,
-                  int microseconds: 0})
+                  int microseconds: 0}) 

[floitsch, 2013/06/25 15:28:02]

Remove trailing space.

[zarah, 2013/06/25 15:54:05]

Done.

       : _duration = days * MICROSECONDS_PER_DAY +
                     hours * MICROSECONDS_PER_HOUR +
                     minutes * MICROSECONDS_PER_MINUTE +
@@ -82,9 +82,12 @@ class Duration implements Comparable<Duration> {
   /**
    * Multiplies this [Duration] by the given [factor] and returns the result
    * as a new [Duration].
+   *
+   * Note when [factor] is a double, and the duration is greater than

[floitsch, 2013/06/25 15:28:02]

Note that ...
or:
Note: ...

[zarah, 2013/06/25 15:54:05]

Done.

+   * 53 bits, precision is lost because of double-precision arithmetic. 
    */
-  Duration operator *(int factor) {
-    return new Duration(microseconds: _duration * factor);
+  Duration operator *(num factor) {
+    return new Duration(microseconds: (_duration * factor).round());
   }
 
   /**