Allow newly activated web contents to update their layout during drags

This fixes an issue where detaching a tab by dragging does not correctly
resize the newly activated contents.

Example:
https://screencast.googleplex.com/cast/NjQ2MDg4MzY0MjM1MTYxNnwzMjcwNjVkNy05ZA

Fast-resize is the culprit here because NativeViewHost::Layout applies a
clip around the visible bounds; this clip is not updated when
fast-resize is enabled, which prevents the visible layout from changing
during a resize. Disabling fast-resize for tab-switches ensures this
clip is removed.

Bug: 429615017
Change-Id: Ib57d80012a3131582776c354249c85ac1f28a61b
Fixed: 429615017
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6825266
Commit-Queue: Kaan Alsan <alsan@chromium.org>
Reviewed-by: Tom Lukaszewicz <tluk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1498455}