Check that a plugin path points to a file before rejecting the plugin because it's 64-bit.
Check that a plugin path points to a file before rejecting the plugin because it's 64-bit.

BUG=75131
TEST=none

Review URL: http://codereview.chromium.org/6635013
Patch from Simon Morris <simonmorris@chromium.org>.

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@77186 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser