Support embedded plugins with MimeHandlerView.
This change adds support for embedded plugins getting loaded via MimeHandlerView.
Changes:
-Changes MimeHandlerViewContainer to kick off a URL request when the content
is embedded. This is done because in that case, a URL request isn't started
automatically by the browser.
-Plumb through the original URL that is used to instantiate the plugin so that it can be loaded (as above).
-Change the extensions PluginManager to allow extensions that are associated
with a MIME type to be handlers for the file extensions which correspond with
that MIME type. This is needed because <embed>ed documents don't typically
specify a MIME type.
Currently the URL request made won't correctly be intercepted as an http stream. This change will be made in a followup CL.
BUG=303491
Review URL: https://codereview.chromium.org/701713003
Cr-Commit-Position: refs/heads/master@{#303152}
10 files changed
