Disable flaky ExtensionsMenuViewBrowserTest.RemoveExtensionShowingPopup

TBR=bsep@chromium.org

Change-Id: I0729df379983a73f7a2a796d8dfec78f81a0202d
Bug: 1049063
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2039513Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Commit-Queue: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#738895}

chrome/browser/ui/views/extensions/extensions_menu_view_browsertest.cc

@@ -357,8 +357,9 @@ IN_PROC_BROWSER_TEST_F(ExtensionsMenuViewBrowserTest, TriggerPopup) {
   EXPECT_TRUE(GetVisibleToolbarActionViews().empty());
 }
 
+// TODO(crbug.com/1049063): Flaky on various platforms.
 IN_PROC_BROWSER_TEST_F(ExtensionsMenuViewBrowserTest,
-                       RemoveExtensionShowingPopup) {
+                       DISABLED_RemoveExtensionShowingPopup) {
   LoadTestExtension("extensions/simple_with_popup");
   ShowUi("");
   VerifyUi();