GitLab

frame_->GetPage() may be null. need to check before use GetDragState
This CL reorder the some checks in MouseEventManager::TryStartDrag
to make sure GetPage is valid before start drag.

Bug: 843502
Change-Id: Ifdf5b20d7132ca4b089c9a5b7652ebbd41370c33
Reviewed-on: https://chromium-review.googlesource.com/1064878
Commit-Queue: Ella Ge <eirage@chromium.org>
Reviewed-by: Navid Zolghadr <nzolghadr@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#561262}