Make methods in Stopwatch getters and rename to be more consistent.

lib/coreimpl/stopwatch_implementation.dart

Index: lib/coreimpl/stopwatch_implementation.dart
diff --git a/lib/coreimpl/stopwatch_implementation.dart b/lib/coreimpl/stopwatch_implementation.dart
index f22f21052727a253eaefbc15a34a15811f7fa5ef..30b4ca262d9f094a9b6ecaf2d5c196a332b62780 100644
--- a/lib/coreimpl/stopwatch_implementation.dart
+++ b/lib/coreimpl/stopwatch_implementation.dart
@@ -50,22 +50,22 @@ class StopwatchImplementation implements Stopwatch {
     }
   }
 
-  int elapsed() {
+  int get elapsedTicks {
     if (_start === null) {
       return 0;
     }
     return (_stop === null) ? (_now() - _start) : (_stop - _start);
   }
 
-  int elapsedInUs() {
-    return (elapsed() * 1000000) ~/ frequency();
+  int get elapsedMicroseconds {
+    return (elapsedTicks * 1000000) ~/ frequency;
   }
 
-  int elapsedInMs() {
-    return (elapsed() * 1000) ~/ frequency();
+  int get elapsedMilliseconds {
+    return (elapsedTicks * 1000) ~/ frequency;
   }
 
-  int frequency() => _frequency();
+  int get frequency => _frequency();
 
   external static int _frequency();
   external static int _now();