Revert of Disable BrowserTest.WindowOpenClose for Mac (patchset #1 id…

…:1 of https://codereview.chromium.org/1093003002/)

Reason for revert:
The Blink problem has been fixed and will roll into Chrome in the next iteration.

Original issue's description:
> Disable BrowserTest.WindowOpenClose for Mac
>
> It's timing out on Mac 10.6 and 10.8 tests, preventing a Blink roll.
>
> TBR=sky@chromium.org,lushnikov@chromium.org
> BUG=478238
>
> Committed: https://crrev.com/64bd184eb5f5e92121318e698fc70d42de2b3f74
> Cr-Commit-Position: refs/heads/master@{#325753}

TBR=sky@chromium.org,lushnikov@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=478238

Review URL: https://codereview.chromium.org/1096393003

Cr-Commit-Position: refs/heads/master@{#326103}

chrome/browser/ui/browser_browsertest.cc

@@ -2074,9 +2074,6 @@ IN_PROC_BROWSER_TEST_F(BrowserTest2, NoTabsInPopups) {
 }
 #endif
 
-// TODO(schenney) Disable on Mac to enable a Blink roll.
-// Re-enable and fix after Blink rolls.
-#if !defined(OS_MACOSX)
 IN_PROC_BROWSER_TEST_F(BrowserTest, WindowOpenClose) {
   base::CommandLine::ForCurrentProcess()->AppendSwitch(
       switches::kDisablePopupBlocking);
@@ -2089,7 +2086,6 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, WindowOpenClose) {
   ui_test_utils::NavigateToURLBlockUntilNavigationsComplete(browser(), url, 2);
   EXPECT_EQ(title, title_watcher.WaitAndGetTitle());
 }
-#endif
 
 // TODO(linux_aura) http://crbug.com/163931
 // Mac disabled: http://crbug.com/169820