Fix up ExtensionResource::CombinePathsSafely so that it can handle paths with .. in them safely.
Fix up ExtensionResource::CombinePathsSafely so that it can handle paths with .. in them safely.

BUG=25131
TEST=Build unit_tests on Mac with default build location that contains a .. in the path.

Review URL: http://codereview.chromium.org/295001

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@29383 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