[multiball] Add a11y identifier to windows.

Adds an identifier for EGTests to each window. This will allow matching
specific windows in tests.

Bug: none
Change-Id: I9d04ee645ec1658181d5580a8f4c2060b6927940
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2463565
Auto-Submit: Stepan Khapugin <stkhapugin@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#816167}

ios/chrome/browser/ui/main/scene_delegate.mm

@@ -39,6 +39,16 @@ NSString* const kOriginDetectedKey = @"OriginDetectedKey";
     // Sizing of the window is handled by UIKit.
     _window = [[ChromeOverlayWindow alloc] init];
     CustomizeUIWindowAppearance(_window);
+
+    if (@available(iOS 13, *)) {
+      // Assign an a11y identifier for using in EGTest.
+      // See comment for [ChromeMatchersAppInterface windowWithNumber:] matcher
+      // for context.
+      self.sceneState.window.accessibilityIdentifier =
+          [NSString stringWithFormat:@"%ld", UIApplication.sharedApplication
+                                                     .connectedScenes.count -
+                                                 1];
+    }
   }
   return _window;
 }

ios/chrome/test/earl_grey/chrome_matchers.h

@@ -13,6 +13,14 @@
 
 namespace chrome_test_util {
 
+// Matcher for a window with a given number.
+// Window numbers are assigned at scene creation. Normally, each EGTest will
+// start with exactly one window with number 0. Each time a window is created,
+// it is assigned an accessibility identifier equal to the number of connected
+// scenes (stored as NSString). This means typically any windows created in a
+// test will have consecutive numbers.
+id<GREYMatcher> WindowWithNumber(int window_number);
+
 // Matcher for element with accessibility label corresponding to |message_id|
 // and accessibility trait UIAccessibilityTraitButton.
 id<GREYMatcher> ButtonWithAccessibilityLabelId(int message_id);

ios/chrome/test/earl_grey/chrome_matchers.mm

@@ -16,6 +16,10 @@ GREY_STUB_CLASS_IN_APP_MAIN_QUEUE(ChromeMatchersAppInterface)
 
 namespace chrome_test_util {
 
+id<GREYMatcher> WindowWithNumber(int window_number) {
+  return [ChromeMatchersAppInterface windowWithNumber:window_number];
+}
+
 id<GREYMatcher> ButtonWithAccessibilityLabel(NSString* label) {
   return [ChromeMatchersAppInterface buttonWithAccessibilityLabel:label];
 }

ios/chrome/test/earl_grey/chrome_matchers_app_interface.h

@@ -15,6 +15,14 @@
 // define the matchers in the app process.
 @interface ChromeMatchersAppInterface : NSObject
 
+// Matcher for a window with a given number.
+// Window numbers are assigned at scene creation. Normally, each EGTest will
+// start with exactly one window with number 0. Each time a window is created,
+// it is assigned an accessibility identifier equal to the number of connected
+// scenes (stored as NSString). This means typically any windows created in a
+// test will have consecutive numbers.
++ (id<GREYMatcher>)windowWithNumber:(int)windowNumber;
+
 // Matcher for element with accessibility label corresponding to |label| and
 // accessibility trait UIAccessibilityTraitButton.
 + (id<GREYMatcher>)buttonWithAccessibilityLabel:(NSString*)label;

ios/chrome/test/earl_grey/chrome_matchers_app_interface.mm

@@ -129,6 +129,12 @@ UIView* SubviewWithAccessibilityIdentifier(NSString* accessibility_id,
 
 @implementation ChromeMatchersAppInterface
 
++ (id<GREYMatcher>)windowWithNumber:(int)windowNumber {
+  return grey_allOf(
+      grey_accessibilityLabel([NSString stringWithFormat:@"%d", windowNumber]),
+      grey_kindOfClass([UIWindow class]), nil);
+}
+
 + (id<GREYMatcher>)buttonWithAccessibilityLabel:(NSString*)label {
   return grey_allOf(grey_accessibilityLabel(label),
                     grey_accessibilityTrait(UIAccessibilityTraitButton), nil);