[ios] Ends InfobarModal editing if tapped outside keyboard.

- This will dismiss the Keyboard if the user taps outside of it.
- If the user taps a view that takes a tap gesture (f.e. a button
like Reveal/Hide password) the keyboard will not be dismissed
since this touch will be handled by the view.

Bug: 911864
Change-Id: I74c0e7098c95cb52e42925f647ce485f548bf43f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1627300Reviewed-by: Chris Lu <thegreenfrog@chromium.org>
Reviewed-by: Peter Lee <pkl@chromium.org>
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#664506}

ios/chrome/browser/ui/infobars/presentation/infobar_modal_presentation_controller.mm

@@ -29,6 +29,13 @@ const CGFloat kModalViewVerticalPadding = 20;
 
 @implementation InfobarModalPresentationController
 
+- (void)presentationTransitionWillBegin {
+  UITapGestureRecognizer* tap =
+      [[UITapGestureRecognizer alloc] initWithTarget:self.presentedView
+                                              action:@selector(endEditing:)];
+  [self.containerView addGestureRecognizer:tap];
+}
+
 - (void)containerViewWillLayoutSubviews {
   self.presentedView.frame = [self frameForPresentedView];