Description of problem:
chrome just can embed plugins via xembed. To be able to view PDFs in chrome one needs a really recent release of mozplugger. See http://code.google.com/p/chromium/issues/detail?id=19587 for more information.
To have it working in chrome one needs then to have a line like the following in mozpluggerrc:
define(ACROREAD, [repeat swallow(acroread) fill needs_xembed : acroread
-openInNewWindow /a "$fragment" "$file"])
Fedora currently has 1.12.1 the version with xembed report is 1.13.3.
it should be fixed in mozplugger-1.14.2-1.fc13 which will be available in f13-update-testing soon. Or you can download it from http://koji.fedoraproject.org/koji/buildinfo?buildID=189076