Change ActiveTabTest to do setup in SetUp rather than its constructor.

BUG=136629
TEST=
TBR=aa@chromium.org

Review URL: https://chromiumcodereview.appspot.com/10703158

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@146279 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/extensions/active_tab_unittest.cc

@@ -64,6 +64,10 @@ class ActiveTabTest : public TabContentsTestHarness {
         extension_without_active_tab(
             CreateTestExtension("without activeTab", false)),
         ui_thread_(BrowserThread::UI, MessageLoop::current()) {
+  }
+
+  virtual void SetUp() {
+    TabContentsTestHarness::SetUp();
     Feature::SetChannelForTesting(chrome::VersionInfo::CHANNEL_UNKNOWN);
   }