reuse the same browser when running webdriver tests

tools/testing/dart/test_suite.dart

Index: tools/testing/dart/test_suite.dart
diff --git a/tools/testing/dart/test_suite.dart b/tools/testing/dart/test_suite.dart
index 6c0ddf60f46e679c55d1c063f1a80fffdcd0649a..d37bf2215f76f8c97423f85457d52a40d1c0e3eb 100644
--- a/tools/testing/dart/test_suite.dart
+++ b/tools/testing/dart/test_suite.dart
@@ -533,9 +533,10 @@ class StandardTestSuite implements TestSuite {
 
       List<String> args;
       if (component == 'webdriver') {
-        args = ['$dartDir/tools/testing/run_selenium.py', '--out=$htmlPath',
+        args = ['$dartDir/tools/testing/run_selenium.py',
+            '--browser=${configuration["browser"]}',

[Emily Fortuna, 2012/02/21 18:19:35]

Not that it really matters, but why did we change the order these arguments are
passed here?

[Jennifer Messerly, 2012/02/21 18:58:43]

At one point I thought I needed --browser first so that could be configured at
startup of run_selenium. The idea is the first 2 args would be part of the
"batch mode" command line, and the last 2 args would be part of the "per test"
command line. I ended up making it handle the --browser though, so this could be
reverted. WDYT?

[Emily Fortuna, 2012/02/21 19:35:33]

Either way is fine. This works for me. I don't have a strong preference one way
or the other.

             '--timeout=${configuration["timeout"] - 2}',
-            '--browser=${configuration["browser"]}'];
+            '--out=$htmlPath'];
       } else {
         args = [
             '$dartDir/tools/testing/drt-trampoline.py',