chore: cherry-pick df77f100c3c2 from chromium

[VerteDinde]

Remove GestureListenerManager as observer before destruction

GestureListenerManager adds itself as InputEventObserver but doesn't
remove itself from the observer list when getting destroyed, which
causes dangling raw pointer failures (use-after-free) if
GestureListenerManager gets destroyed before RenderWidgetHost and
dangling raw pointer checks are enabled.

Thus remove GestureListenerManager as observer when
GestureListenerManager is destructed.

Fixes regression from the following change:
https://chromium-review.googlesource.com/c/chromium/src/+/5887051

Change-Id: Ia24a0d4b80533e3a6406e7398351f37c682211fe

Bug: 378464985
Change-Id: Ia24a0d4b80533e3a6406e7398351f37c682211fe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6012419
Reviewed-by: Bo Liu [email protected]
Commit-Queue: Olle Liljenzin [email protected]
Reviewed-by: Yaron Friedman [email protected]
Cr-Commit-Position: refs/heads/main@{#1386220}

Notes: Backported fix for 378464985.

[ckerr]

Patch fails to apply:

Applying: Remove GestureListenerManager as observer before destruction
Patch failed at 0139 Remove GestureListenerManager as observer before destruction
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