[VizHitTesting] Re-enable DragAndDropBrowserTest.CrossSiteDrag on ChromeOS

The failure on ChromeOS started when VizHitTesting was turned on by
default and it should be fixed by crrev.com/c/1693442. Tested locally
and the test is no longer failing.

Bug: 997676
Change-Id: I71892e0b1ffb1829f73fac3b5ee6572f770a4021
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1770080
Commit-Queue: Yi Gu <yigu@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#690352}

chrome/browser/ui/views/drag_and_drop_interactive_uitest.cc

@@ -1198,9 +1198,6 @@ void DragAndDropBrowserTest::DragImageFromDisappearingFrame_Step3(
 // a drag-and-drop loop run by Windows OS.
 #if defined(OS_WIN)
 #define MAYBE_CrossSiteDrag DISABLED_CrossSiteDrag
-#elif defined(OS_CHROMEOS)
-// Flaky: https://crbug.com/835774
-#define MAYBE_CrossSiteDrag DISABLED_CrossSiteDrag
 #else
 #define MAYBE_CrossSiteDrag CrossSiteDrag
 #endif