Fix some scan_sources.py dependencies
Fix some scan_sources.py dependencies

Search for include files relative to the
directory of the file that included them.

BUG=169539
TEST=manual, run gyp from chrome and verify includes are found

Review URL: https://codereview.chromium.org/11882002

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@10614 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

Lind-Project/native_client,Lind-Project/native_client,Lind-Project/native_client,Lind-Project/native_client,Lind-Project/native_client,Lind-Project/native_client