[ MimeHandlerView ] Enable a test on Linux

The test should pass now after crrev.com/c/1407596.

TBR=wjmaclean@chromium.org

Bug: 659750, 918784
Change-Id: Ic71e2524804fd01dc7ee7e93af988465db20c95f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1547296Reviewed-by: Ehsan Karamad <ekaramad@chromium.org>
Commit-Queue: Ehsan Karamad <ekaramad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#646260}

extensions/browser/guest_view/mime_handler_view/mime_handler_view_browsertest.cc

@@ -218,13 +218,8 @@ IN_PROC_BROWSER_TEST_P(MimeHandlerViewCrossProcessTest,
 // to load a MimeHandlerView. The test passes if MHV loads. This is to catch the
 // potential race between the cross-origin renderer initiated navigation and
 // the navigation to "about:blank" started from the browser.
-#if defined(OS_LINUX)
-#define MAYBE_NavigationRaceFromEmbedder DISABLED_NavigationRaceFromEmbedder
-#else
-#define MAYBE_NavigationRaceFromEmbedder NavigationRaceFromEmbedder
-#endif
 IN_PROC_BROWSER_TEST_P(MimeHandlerViewCrossProcessTest,
-                       MAYBE_NavigationRaceFromEmbedder) {
+                       NavigationRaceFromEmbedder) {
   if (!is_cross_process_mode()) {
     // Note that this test would pass trivially with BrowserPlugin-based guests
     // because loading a plugin is quite independent from navigating a plugin.