PDF: Remove third_party/pdfium from the checklicenses.py suppressions list.

All licensing issues were fixed in pdfium/checklicenses last week.

BUG=374943
TBR=jam@chromium.org

Review URL: https://codereview.chromium.org/307933013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@274407 0039d316-1c4b-4281-b951-d872f2087c98

tools/checklicenses/checklicenses.py

@@ -261,9 +261,6 @@ PATH_SPECIFIC_WHITELISTED_LICENSES = {
     'third_party/ocmock/OCMock': [  # http://crbug.com/98454
         'UNKNOWN',
     ],
-    'third_party/pdfium': [  # http://crbug.com/374943
-        'UNKNOWN',
-    ],
     'third_party/ply/__init__.py': [
         'UNKNOWN',
     ],