Added wxStopWatch::TimeInMicro() for better precision time measurement.

Also simplify/streamline wxStopWatch implementation and replace confusingly
named m_pause with more clear m_elapsedBeforePause.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@69835 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

tests/events/stopwatch.cpp

@@ -55,13 +55,22 @@ CPPUNIT_TEST_SUITE_NAMED_REGISTRATION( StopWatchTestCase, "StopWatchTestCase" );
 
 void StopWatchTestCase::Misc()
 {
-    static const long tolerance = 100;  // in ms
+    static const long tolerance = 10;  // in ms
 
     wxStopWatch sw;
     long t;
+    wxLongLong usec;
 
     sw.Pause();         // pause it immediately
 
+    // verify that almost no time elapsed
+    usec = sw.TimeInMicro();
+    WX_ASSERT_MESSAGE
+    (
+        ("Elapsed time was %" wxLongLongFmtSpec "dus", usec),
+        usec < tolerance*1000
+    );
+
     wxSleep(1);
     t = sw.Time();