Add and rename histograms for the new DB files.
Add and rename histograms for the new DB files.

The Thumbnails file is renamed to Favicons.
The new "Top Sites" DB file is added.

TEST=about:histograms
BUG=none

Review URL: http://codereview.chromium.org/3113002

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@56374 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