Use attached browser CreateParams in CreateBrowserForDrag

Use the attached browser CreateParams rather than
BrowserList GetLastActive.

It feels safer that the attached browser will always
be the one that we want whereas BrowserList GetLastActive
may not be so reliable.

Bug: 1012169
Change-Id: Ifbbc13aa797db7942f5ce1d52decdac264c5d927
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1862875
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Auto-Submit: Joel Hockey <joelhockey@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#706220}

chrome/browser/ui/views/tabs/tab_drag_controller.cc

@@ -1968,7 +1968,10 @@ Browser* TabDragController::CreateBrowserForDrag(
   *drag_offset = point_in_screen - new_bounds.origin();
 
   Browser::CreateParams create_params =
-      BrowserList::GetInstance()->GetLastActive()->create_params();
+      BrowserView::GetBrowserViewForNativeWindow(
+          GetAttachedBrowserWidget()->GetNativeWindow())
+          ->browser()
+          ->create_params();
   create_params.user_gesture = true;
   create_params.in_tab_dragging = true;
   create_params.initial_bounds = new_bounds;