REGRESSION(r?): Web Inspector: Reloading no longer picks up changes in source files

[Nikita Vasilyev]

Developing is harder now that reloading Web Inspector doesn't pick up source code changes.

Steps:
1. Open Web Inspector
2. Make some WI source files changes
3. Right-click anywhere in Web Inspector
4. Click "Reload Web Inspector"

Actual:
Web Inspector reloads with the source files *before* the changes were made.

Expected:
Web Inspector reloads with the latest sources.

[Nikita Vasilyev]

Created attachment 356074 [details]
[Screenshot] Empty Elements tab

Opening a second level inspector and pressing Command-R reloads WI [1] as expected.

However, the Elements tab is shown empty.

[Joseph Pecoraro]

The old reload would do:

    location.reload()

Which ultimately does a load ignoring the cache in WebCore:

    void FrameLoader::reload(OptionSet<ReloadOption> options)
    {
        ...
        ResourceRequest& request = loader->request();

        // FIXME: We don't have a mechanism to revalidate the main resource without reloading at the moment.
        request.setCachePolicy(ResourceRequestCachePolicy::ReloadIgnoringCacheData);
        ...
    }

The new reload of Web Inspector (for PSON) - InspectorFrontendHost.reopen, just closes and opens the Web Inspector. This does an initial WebPageProxy::loadRequest which doesn't ignore the cache.

    void WebInspectorProxy::openLocalInspectorFrontend(bool canAttach, bool underTest)
    {
        ...
        m_inspectorPage->loadRequest(URL(URL(), m_underTest ? WebInspectorProxy::inspectorTestPageURL() : WebInspectorProxy::inspectorPageURL()));
    }

If we wanted to get this working for inspector² we would need some way to open the inspector ignoring the cache.