[NaCl Docs] Cleanup dynamic loading docs.

Removed a lot of (IMHO redundant) detail and updated
to match current state of the demo.

R=binji@chromium.org

Review URL: https://codereview.chromium.org/56463002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232523 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232523
Enable Google Now on trybots (and all users on Trunk).

BUG=164227
R=asvitkine@chromium.org, kalman@chromium.org, robliao@chromium.org, skare@chromium.org

Review URL: https://codereview.chromium.org/48103003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232524 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232524