[iOS] Share extension - Text sharing UI

This CL adds the text sharing UI for the new share extension.

Bug: 396326825
Change-Id: Id019c7d90e4dc6adfed437928634d5827416f01d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6343098
Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Commit-Queue: Elmehdi Rahmaoui <erahmaoui@google.com>
Cr-Commit-Position: refs/heads/main@{#1431760}

ios/chrome/share_extension/extended_share_view_controller.mm

@@ -279,7 +279,14 @@ const CGFloat kShareSheetCornerRadius = 20;
 - (void)handleText:(id)idText
            forItem:(NSExtensionItem*)item
          withError:(NSError*)error {
-  // TODO(crbug.com/396326361): Handle shared text.
+  self.shareText = [[item attributedContentText] string];
+  self.shareItem = item;
+
+  if (self.shareText) {
+    [self displayShareSheet];
+  } else {
+    [self displayErrorView];
+  }
 }
 
 - (void)loadElementsFromContext {

ios/chrome/share_extension/share_extension_sheet.mm

@@ -270,8 +270,11 @@ NSString* const kCustomMinimizedDetentIdentifier = @"customMinimizedDetent";
 }
 
 - (UIView*)configureSharedTextView {
-  // TODO(crbug.com/396326361): Add text sharing ui configuration.
-  return nil;
+  UILabel* sharedTextLabel = [[UILabel alloc] init];
+  sharedTextLabel.text = self.sharedText;
+  sharedTextLabel.numberOfLines = 0;
+
+  return sharedTextLabel;
 }
 
 - (UIImageView*)configureSnapshotView {