Disable WebViewTest.WebViewInBackgroundPage

Disable the test on other platforms because the test is also timeout on
them.

Bug: 403325
Change-Id: I5e544c8392f69c251a9da6c327d6eadce9b53e76
Tbr: wjmaclean@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2136030Reviewed-by: Owen Min <zmin@chromium.org>
Commit-Queue: Owen Min <zmin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#756420}

chrome/browser/apps/guest_view/web_view_browsertest.cc

@@ -3390,15 +3390,9 @@ IN_PROC_BROWSER_TEST_F(WebViewTest, TestPlugin) {
   TestHelper("testPlugin", "web_view/shim", NEEDS_TEST_SERVER);
 }
 
-#if defined(OS_WIN)
-// Test is disabled on Windows because it times out often.
+// Test is disabled because it times out often.
 // http://crbug.com/403325
-#define MAYBE_WebViewInBackgroundPage \
-    DISABLED_WebViewInBackgroundPage
-#else
-#define MAYBE_WebViewInBackgroundPage WebViewInBackgroundPage
-#endif
-IN_PROC_BROWSER_TEST_F(WebViewTest, MAYBE_WebViewInBackgroundPage) {
+IN_PROC_BROWSER_TEST_F(WebViewTest, DISABLED_WebViewInBackgroundPage) {
   ASSERT_TRUE(StartEmbeddedTestServer());
   ASSERT_TRUE(RunExtensionTest("platform_apps/web_view/background"))
       << message_;