[Mac] Trace input method activation call sites

Opening a browser window with an input method such as Japanese selected
can block the main thread while AppKit activates the input method for
the focused location bar. In a trace this wait is only an untraced gap
inside Widget::Show, so attributing it has needed a custom build.

Add trace events around the calls in which AppKit activates the input
method: the +[NSTextInputContext currentInputContext] query in
-[BridgedContentView needsUpdateWindows], and -[NSApp updateWindows],
which BrowserCrApplication now overrides only to trace it. There is no
behavior change.

Bug: b:567089673
Change-Id: I26aea6fbd191ed4fc7bfa96e32b462426a6a6964
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8553617
Commit-Queue: Ming-Ying Chung <mych@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1717299}