The `currentPath` parameter passed to our metrics utility had been
passed the full URL rather than just the path, contrary to what the
name would imply. We only used the path portion, so passing the full
URL did lead to complications.
Now just the `pathname` is passed in, rather than the full URL. This
simplifies the metrics logic, and it incidentally fixes two bugs.
The main bug fixed is regarding Firefox metrics. Previously we had
assumed the `currentPath` would start with `chrome-extension://`, which
of course was not true on Firefox. This lead to us incorrectly parsing
the `currentPath`, so path tracking was broken for Firefox events.
This broken parsing is now bypassed entirely, so metrics should now
work the same on Firefox as on Chrome.
The second bug was that we were incorrectly setting the tracking URL
for background events during tests. As a result, we were incorrectly
detecting ourselves as an internal site that had referred the user to
us. But this was not of major concern, since it only affected test
metrics (which get sent to the development Matomo project).
Lastly, this change let us discard the `pathname` parameter used in
the `overrides` parameter of the `metricsEvent` function. Now that
`currentPath` is equivalent to `pathname`, the `pathname` parameter is
redundant.
A new page has been created for viewing assets. This replaces the old
`selectedToken` state, which previously would augment the home page
to show token-specific information.
The new asset page shows the standard token overview as seen previously
on the home page, plus a history filtered to show just transactions
relevant to that token.
The actions that were available in the old token list menu have been
moved to a "Token Options" menu that mirrors the "Account Options"
menu.
The `selectedTokenAddress` state has been removed, as it is no longer
being used for anything.
`getMetaMetricState` has been renamed to `getBackgroundMetaMetricState`
because its sole purpose is extracting data from the background state
to send metrics from the background. It's not really a selector, but
it was convenient for it to use the same selectors the UI uses to
extract background data, so I left it there for now.
A new Redux store has been added to track state related to browser history.
The most recent "overview" page (i.e. the home page or the asset page) is
currently being tracked, so that actions taken from the asset page can return
the user back to the asset page when the action has finished.
