Add the pdf plugin's source in src\pdf.

chrome/chrome_tests.gypi

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 {
   'includes': [
     'js_unittest_vars.gypi',
   ],
   'targets': [
     {
       'target_name': 'interactive_ui_tests',
@@ skipping 1752 matching lines @@
           'sources/': [
             ['exclude', '^browser/safe_browsing/'],
             ['exclude', '^renderer/safe_browsing/'],
           ],
         }],
         ['enable_captive_portal_detection!=1', {
           'sources/': [
             ['exclude', '^browser/captive_portal/'],
           ],
         }],
-        ['internal_pdf', {
-          'dependencies': [
-            '../pdf/pdf.gyp:pdf',
-          ],
-        }],
         ['enable_webrtc==0', {
           'sources!': [
             'browser/extensions/api/webrtc_audio_private/webrtc_audio_private_browsertest.cc',
             'browser/extensions/api/webrtc_logging_private/webrtc_logging_private_apitest.cc',
             'browser/media/chrome_webrtc_browsertest.cc',
             'browser/media/chrome_webrtc_disable_encryption_flag_browsertest.cc',
           ],
         }],
         ['OS=="win"', {
           'sources': [
@@ skipping 1193 matching lines @@
             ['enable_webrtc==1', {
               'dependencies': [
                 '../third_party/libjingle/libjingle.gyp:libjingle_webrtc'
               ]
             }],
           ],
         }]
     }],
   ],  # 'conditions'
 }