Fixed assertions in SearchString.
Fixed assertions in SearchString.

BUG=None
TEST=Test searching for text in PDF. Shoud not DCHECK in debug builds.

Review URL: http://codereview.chromium.org/3573010

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@61572 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