[SharingHub] Exclude first party apps when the tab is null.

Bug: 1133398
Change-Id: Ie8787bd6f5772805a94c972163cd8a4e7735ef03
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2442097Reviewed-by: Kyle Milka <kmilka@chromium.org>
Commit-Queue: Sophey Dong <sophey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812945}

chrome/android/java/src/org/chromium/chrome/browser/share/ShareDelegateImpl.java

@@ -302,7 +302,8 @@ public class ShareDelegateImpl implements ShareDelegate {
                 long shareStartTime, boolean sharingHubEnabled) {
             if (chromeShareExtras.shareDirectly()) {
                 ShareHelper.shareWithLastUsedComponent(params);
-            } else if (sharingHubEnabled && !chromeShareExtras.sharingTabGroup()) {
+            } else if (sharingHubEnabled && !chromeShareExtras.sharingTabGroup()
+                    && tabProvider.get() != null) {
                 // TODO(crbug.com/1085078): Sharing hub is suppressed for tab group sharing.
                 // Re-enable it when tab group sharing is supported by sharing hub.
                 ShareSheetCoordinator coordinator = new ShareSheetCoordinator(controller,