Context menu egtests, plus related utilities.

ios/testing/earl_grey/matchers.mm

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "ios/testing/earl_grey/matchers.h"
+
+namespace testing {
+
+id<GREYMatcher> contextMenuItemWithText(NSString* text) {
+  // Both tablet and phone house context menu views inside an alert controller
+  // view (on tablet that view is itself inside a popover view).
+  id<GREYMatcher> context_menu_container =
+      grey_kindOfClass(NSClassFromString(@"_UIAlertControllerView"));
+
+  return grey_allOf(grey_ancestor(context_menu_container), grey_interactable(),
+                    grey_text(text), nil);
+}
+
+id<GREYMatcher> elementToDismissContextMenu(NSString* cancel_text) {
+  UIUserInterfaceIdiom idiom = [[UIDevice currentDevice] userInterfaceIdiom];
+  if (idiom == UIUserInterfaceIdiomPad) {
+    // On iPad the context menu is dismissed by tapping on something
+    // that isn't the popover. UIKit conveniently labels this element.
+    return grey_accessibilityID(@"PopoverDismissRegion");
+  } else {
+    // On iPhone the context menu is dismissed by tapping on the "Cancel" item.
+    return contextMenuItemWithText(cancel_text);
+  }
+}
+
+}  // namespace testing