Properly load Dartium from the Dart Editor when possible.

lib/src/runner/browser/dartium.dart

Index: lib/src/runner/browser/dartium.dart
diff --git a/lib/src/runner/browser/dartium.dart b/lib/src/runner/browser/dartium.dart
index ecb3289c9ae62ac4abd251d8fda367ab654b3381..1672b50124b8474e29f0b9284bfb30369ea5984c 100644
--- a/lib/src/runner/browser/dartium.dart
+++ b/lib/src/runner/browser/dartium.dart
@@ -96,7 +96,7 @@ class Dartium implements Browser {
       if (!new File(p.join(dir, "DartEditor.exe")).existsSync()) return null;
 
       var dartium = p.join(dir, "chromium\\chrome.exe");
-      return new File(dartium).existsSync() ? null : dartium;
+      return new File(dartium).existsSync() ? dartium : null;
     }
 
     if (Platform.isMacOS) {
@@ -107,13 +107,13 @@ class Dartium implements Browser {
 
       var dartium = p.join(
           dir, "chromium/Chromium.app/Contents/MacOs/Chromium");

[kevmoo, 2015/04/16 22:18:33]

MasO*S*

[nweiz, 2015/04/16 22:21:34]

Done.

-      return new File(dartium).existsSync() ? null : dartium;
+      return new File(dartium).existsSync() ? dartium : null;
     }
 
     assert(Platform.isLinux);
     if (!new File(p.join(dir, "DartEditor")).existsSync()) return null;
 
     var dartium = p.join(dir, "chromium", "chrome");
-    return new File(dartium).existsSync() ? null : dartium;
+    return new File(dartium).existsSync() ? dartium : null;
   }
 }