Reland"Add AX ID for Cancel and Done button on Translate Language Picker."

This reverts commit 6163e501.

The original CL's test fails on iPhone 5s, iOS 9.0 because the 
accessibility identifiers of the buttons are not set even though 
setAccessibilityIdentifier is called explicitly in the code, and it
looks like there is nothing we can do about it. This CL fixes the issue
by keeping using accessbilityLabel on iOS 9 and iOS 10, and switch to
use accessibilityID on iOS 11, and will clean this code up once the
support for iOS 10 is dropped.

Original change's description:
> Add AX ID for Cancel and Done button on Translate Language Picker.
> 
> Currently, the test uses the following matchers to find the cancel and
> done button on language picker:
> 
> grey_allOf(chrome_test_util::ButtonWithAccessibilityLabel(@"Cancel"),
>                     grey_userInteractionEnabled(), nil);
> 
> This is not bullet proof and may break any time, and this CL fixes the
> issue by adding AX ID to both the cancel and done buttons.

Bug: 750344
Change-Id: I57d1c716118049516d93853da77c25d85385aae0
Reviewed-on: https://chromium-review.googlesource.com/599124
Commit-Queue: Yuke Liao <liaoyuke@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491774}

ios/chrome/browser/translate/before_translate_infobar_controller.h

@@ -7,6 +7,14 @@
 
 #include "ios/chrome/browser/infobars/infobar_controller.h"
 
+// The accessibility identifier of the cancel button on language picker view.
+// NOTE: this should not be used on iOS 9 for testing.
+extern NSString* const kLanguagePickerCancelButtonId;
+
+// The accessibility identifier of the done button on language picker view.
+// NOTE: this should not be used on iOS 9 for testing.
+extern NSString* const kLanguagePickerDoneButtonId;
+
 @interface BeforeTranslateInfoBarController : InfoBarController
 
 @end

ios/chrome/browser/translate/before_translate_infobar_controller.mm

@@ -22,6 +22,9 @@
 #error "This file requires ARC support."
 #endif
 
+NSString* const kLanguagePickerCancelButtonId = @"LanguagePickerCancelButton";
+NSString* const kLanguagePickerDoneButtonId = @"LanguagePickerDoneButton";
+
 namespace {
 
 CGFloat kNavigationBarHeight = 44;
@@ -302,10 +305,12 @@ NSTimeInterval kPickerAnimationDurationInSeconds = 0.2;
       initWithBarButtonSystemItem:UIBarButtonSystemItemDone
                            target:self
                            action:@selector(languageSelectionDone)];
+  [doneButton setAccessibilityIdentifier:kLanguagePickerDoneButtonId];
   UIBarButtonItem* cancelButton = [[UIBarButtonItem alloc]
       initWithBarButtonSystemItem:UIBarButtonSystemItemCancel
                            target:self
                            action:@selector(dismissLanguageSelectionView)];
+  [cancelButton setAccessibilityIdentifier:kLanguagePickerCancelButtonId];
   UINavigationItem* item = [[UINavigationItem alloc] initWithTitle:@""];
   [item setRightBarButtonItem:doneButton];
   [item setLeftBarButtonItem:cancelButton];

ios/chrome/browser/translate/translate_egtest.mm

@@ -5,6 +5,7 @@
 #import <XCTest/XCTest.h>
 
 #include "base/command_line.h"
+#include "base/ios/ios_util.h"
 #include "base/mac/bind_objc_block.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/sys_string_conversions.h"
@@ -19,6 +20,7 @@
 #import "components/translate/ios/browser/js_translate_manager.h"
 #import "components/translate/ios/browser/language_detection_controller.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
+#include "ios/chrome/browser/translate/before_translate_infobar_controller.h"
 #include "ios/chrome/browser/translate/chrome_ios_translate_client.h"
 #import "ios/chrome/test/app/chrome_test_util.h"
 #import "ios/chrome/test/app/tab_test_util.h"
@@ -108,17 +110,23 @@ NSString* GetTranslateInfobarSwitchLabel(const std::string& language) {
 }
 
 // Returns a matcher for the button with label "Cancel" in the language picker.
-// TODO(crbug.com/750344): Change the matcher to use accessibility ID.
+// The language picker uses the system accessibility labels, thus no IDS_CANCEL.
 id<GREYMatcher> LanguagePickerCancelButton() {
-  return grey_allOf(chrome_test_util::ButtonWithAccessibilityLabel(@"Cancel"),
-                    grey_userInteractionEnabled(), nil);
+  // Setting A11y id on this button doesn't work on iOS 9.0.
+  if (base::ios::IsRunningOnIOS10OrLater())
+    return grey_accessibilityID(kLanguagePickerCancelButtonId);
+
+  return chrome_test_util::ButtonWithAccessibilityLabel(@"Cancel");
 }
 
 // Returns a matcher for the button with label "Done" in the language picker.
-// TODO(crbug.com/750344): Change the matcher to use accessibility ID.
+// The language picker uses the system accessibility labels, thus no IDS_DONE.
 id<GREYMatcher> LanguagePickerDoneButton() {
-  return grey_allOf(chrome_test_util::ButtonWithAccessibilityLabel(@"Done"),
-                    grey_userInteractionEnabled(), nil);
+  // Setting A11y ID on this button doesn't work on iOS 9.0.
+  if (base::ios::IsRunningOnIOS10OrLater())
+    return grey_accessibilityID(kLanguagePickerDoneButtonId);
+
+  return chrome_test_util::ButtonWithAccessibilityLabel(@"Done");
 }
 
 #pragma mark - TestResponseProvider
@@ -615,8 +623,6 @@ using translate::LanguageDetectionController;
       selectElementWithMatcher:chrome_test_util::ButtonWithAccessibilityLabel(
                                    kFrench)] performAction:grey_tap()];
 
-  // The language picker uses the system accessibility labels (thus no
-  // IDS_CANCEL here).
   [[EarlGrey selectElementWithMatcher:LanguagePickerCancelButton()]
       assertWithMatcher:grey_notNil()];