Remove chrome_child.dll.pdb from isolate file because it's not there on the bots.

chrome/telemetry_gpu_test.isolate

 # Copyright (c) 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': [
     'telemetry.isolate',
   ],
   'conditions': [
     ['OS=="android" or OS=="linux" or OS=="mac" or OS=="win"', {
       # This isolate allows any of the GPU tests, including the WebGL
@@ skipping 12 matching lines @@
           '../content/test/gpu/run_gpu_test.py',
         ],
       },
     }],
     # These PDBs are needed in order to get reasonable stack traces if
     # an assertion fires or a crash occurs. Add more as necessary.
     ['OS=="win" and (fastbuild==0 or fastbuild==1)', {
       'variables': {
         'isolate_dependency_tracked': [
           '<(PRODUCT_DIR)/chrome.exe.pdb',
-          '<(PRODUCT_DIR)/chrome_child.dll.pdb',
         ],
       },
     }],
     ['OS=="win" and component=="shared_library" and (fastbuild==0 or fastbuild==1)', {
       'variables': {
         'isolate_dependency_tracked': [
           '<(PRODUCT_DIR)/base.dll.pdb',
           '<(PRODUCT_DIR)/blink_platform.dll.pdb',
           '<(PRODUCT_DIR)/blink_web.dll.pdb',
           '<(PRODUCT_DIR)/content.dll.pdb',
         ],
       },
     }],
   ]
 }