internal/trace/traceviewer: make the mmu handler more self-contained
The last change made the MMU rendering code common and introduced a new
API, but it was kind of messy. Part of the problem was that some of the
Javascript in the template for the main page referred to specific
endpoints on the server.
Fix this by having the Javascript access the same endpoint but with a
different query variable. Now the Javascript code doesn't depend on
specific endpoints, just on query variables for the current endpoint.
For #60773.
For #63960.
Change-Id: I1c559d9859c3a0d62e2094c9d4ab117890b63b31
Reviewed-on: https://go-review.googlesource.com/c/go/+/541259
Auto-Submit: Michael Knyszek <mknyszek@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>