Only inject content scripts into HTML documents. Previously we would inject into SVG and raw XML documents as well.
Only inject content scripts into HTML documents. Previously we would inject into SVG and raw XML documents as well.

Injecting into SVG could conceivably be a feature, but I expect it would count as a "bug" more often than that, so I'm starting conservative.

BUG=39845

Review URL: http://codereview.chromium.org/2389004

git-svn-id: http://src.chromium.org/svn/trunk/src@48693 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 60e23eb16d107dafa3c440122ce93c4605e66bac
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser