[Merge to M100] wm: Another speculative fix for the crash during wind…

…ow dragging

This is another specutlative fix for the crash that happens during
dragging. It's possible that when dragging a maximized window, restoring
the maximized window may cause the window being destroyed. Early return
in this case.

(cherry picked from commit 2eb6c28)

Bug: 1200599
Change-Id: Ib8c49ee418e6fd1d3549de6e7b8ec71f6a35e412
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3543511
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Xiaoqian Dai <xdai@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#984102}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3553687
Cr-Commit-Position: refs/branch-heads/4896@{#872}
Cr-Branched-From: 1f63ff4-refs/heads/main@{#972766}

ash/wm/workspace/workspace_window_resizer.cc

@@ -713,9 +713,21 @@ void WorkspaceWindowResizer::Drag(const gfx::PointF& location_in_parent,
             // Update the maximized window so that it looks like it has been
             // restored (i.e. update the caption buttons and height of the
             // browser frame).
+
+            // TODO(http://crbug.com/1200599): Speculative, remove if not fixed.
+            // Change window property kFrameRestoreLookKey or window bounds may
+            // cause the window being destroyed during the drag and return early
+            // if that's the case.
+            base::WeakPtr<WorkspaceWindowResizer> resizer(
+                weak_ptr_factory_.GetWeakPtr());
             window_state()->window()->SetProperty(kFrameRestoreLookKey, true);
+            if (!resizer)
+              return;
             CrossFadeAnimation(window_state()->window(), bounds,
                                /*maximize=*/false);
+            if (!resizer)
+              return;
+
             base::RecordAction(
                 base::UserMetricsAction("WindowDrag_Unmaximize"));
           } else if (window_state()->IsSnapped()) {