Do not exclude pdf from DEPS check.

DEPS

 # This file is automatically processed to create .DEPS.git which is the file
 # that gclient uses under git.
 #
 # See http://code.google.com/p/chromium/wiki/UsingGit
 #
 # To test manually, run:
 #   python tools/deps2git/deps2git.py -o .DEPS.git -w <gclientdir>
 # where <gcliendir> is the absolute path to the directory containing the
 # .gclient file (the parent of "src").
 #
@@ skipping 564 matching lines @@
 ]
 
 
 # checkdeps.py shouldn't check include paths for files in these dirs:
 skip_child_includes = [
   "breakpad",
   "delegate_execute",
   "metro_driver",
   "native_client_sdk",
   "o3d",
-  "pdf",
   "sdch",
   "skia",
   "testing",
   "third_party",
   "v8",
   "win8",
 ]
 
 
 hooks = [
@@ skipping 172 matching lines @@
                 "-s", "src/build/linux/bin/eu-strip.sha1",
     ],
   },
   {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     "name": "gyp",
     "pattern": ".",
     "action": ["python", "src/build/gyp_chromium"],
   },
 ]