Remove usage of Tab's |url| property from ShareToDataBuilder.

ios/chrome/browser/ui/activity_services/share_to_data_builder.mm

 // Copyright 2017 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.
 
 #include "ios/chrome/browser/ui/activity_services/share_to_data_builder.h"
 
 #include "base/logging.h"
 #include "ios/chrome/browser/tabs/tab.h"
 #include "ios/chrome/browser/ui/activity_services/chrome_activity_item_thumbnail_generator.h"
 #include "ios/chrome/browser/ui/activity_services/share_to_data.h"
@@ skipping 13 matching lines @@
   if (!tab.webState)
     return nil;
   DCHECK(tab);
   // If the original page title exists, it is expected to match the tab title.
   // If this ever changes, then a decision has to be made on which one should
   // be used for sharing.
   DCHECK(!tab.originalTitle || [tab.originalTitle isEqualToString:tab.title]);
   BOOL isPagePrintable = [tab viewForPrinting] != nil;
   ThumbnailGeneratorBlock thumbnailGenerator =
       activity_services::ThumbnailGeneratorForTab(tab);
-  return [[ShareToData alloc] initWithURL:tab.url
+  return [[ShareToData alloc] initWithURL:tab.lastCommittedURL

[kkhorimoto, 2017/04/14 20:35:24]

If a user is attempting to share a page, we can assume they're interested in
sharing the visible content, not a pending load.

[sdefresne, 2017/04/18 15:56:49]

I personally frequently share pages that are still loading (e.g. sending to
"Instapaper" pages that are slow to load because they are under heavy load
because they were featured on a high visibility site like reddit). I think we
should test pending load here.

[Eugene But (OOO till 7-30), 2017/04/18 16:16:47]

I think we should be consistent with other features and platforms. Bookmarks,
f.e. use lastCommitted URL on Desktop and this is something that I would expect
from iOS as well. Because different people may have different opinions, how
about we start a team discussion on this topic? This is product level decision,
not engineering decision.

[kkhorimoto, 2017/05/31 22:12:36]

I agree with Eugene that it should be last committed, but I've sent an email to
bling-team@ for more discussion since this is a product-level decision.

[kkhorimoto, 2017/06/01 19:52:23]

Changed to visible per discussion on email thread.

                                     title:tab.title
                           isOriginalTitle:(tab.originalTitle != nil)
                           isPagePrintable:isPagePrintable
                        thumbnailGenerator:thumbnailGenerator];
 }
 
 }  // namespace activity_services