Mac: use last committed URL when enabling/disabling share menu

Previously, we were using chrome::CanEmailPageLocation to check if share
should be enabled, which checked against the current URL, but user the
last committed URL to actually perform the share.

I'm honestly not sure if the non-Mac email behavior is correct and
would like to side-step that for a moment. On the Mac, we really want
the committed URL since we pass along a screenshot to the share service.

This changes adapts the logic of CanEmailPageLocation to the committed
URL and inlines it in the share menu controller.

Bug: 1095807
Change-Id: Icad4f3766335d0156edf6d1078ea06b328cfed06
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2261613Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Leonard Grey <lgrey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#781955}

chrome/browser/ui/cocoa/share_menu_controller.mm

@@ -48,6 +48,17 @@ NSString* const kOpenSharingSubpaneProtocolValue = @"com.apple.share-services";
 NSString* const kRemindersSharingServiceName =
     @"com.apple.reminders.RemindersShareExtension";
 
+bool CanShare() {
+  Browser* last_active_browser = chrome::FindLastActive();
+  return last_active_browser &&
+         last_active_browser->location_bar_model()->ShouldDisplayURL() &&
+         last_active_browser->tab_strip_model()->GetActiveWebContents() &&
+         last_active_browser->tab_strip_model()
+             ->GetActiveWebContents()
+             ->GetLastCommittedURL()
+             .is_valid();
+}
+
 }  // namespace
 
 @implementation ShareMenuController {
@@ -82,12 +93,7 @@ NSString* const kRemindersSharingServiceName =
   [menu removeAllItems];
   [menu setAutoenablesItems:NO];
 
-  Browser* lastActiveBrowser = chrome::FindLastActive();
-  BOOL canShare =
-      lastActiveBrowser != nullptr &&
-      // Avoid |CanEmailPageLocation| segfault in interactive UI tests
-      lastActiveBrowser->tab_strip_model()->GetActiveWebContents() != nullptr &&
-      chrome::CanEmailPageLocation(lastActiveBrowser);
+  bool canShare = CanShare();
   // Using a real URL instead of empty string to avoid system log about relative
   // URLs in the pasteboard. This URL will not actually be shared to, just used
   // to fetch sharing services that can handle the NSURL type.
@@ -180,6 +186,7 @@ NSString* const kRemindersSharingServiceName =
 
 // Performs the share action using the sharing service represented by |sender|.
 - (void)performShare:(NSMenuItem*)sender {
+  DCHECK(CanShare());
   Browser* browser = chrome::FindLastActive();
   DCHECK(browser);
   [self saveTransitionDataFromBrowser:browser];