When enabled, adding of a new range that overlaps with an existing one can be a successful operation. The range which ends at the higher address will be shrunk down by moving its start position to a higher address so that it does not overlap anymore.
This change is required to fix http://crbug/611824. The actual fix will come in a separate CL.
R=mmandlis@chromium.org
Review URL: https://codereview.chromium.org/2029953003 .
