Add namespace and re-arrange PDFium's local copy of chromium /base.

third_party/third_party.gyp

 # Copyright 2014 PDFium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'targets': [
     {
       'target_name': 'bigint',
       'type': 'static_library',
       'sources': [
@@ skipping 43 matching lines @@
         'freetype/src/psnames/psmodule.c',
         'freetype/src/raster/raster.c',
         'freetype/src/sfnt/sfnt.c',
         'freetype/src/smooth/smooth.c',
         'freetype/src/truetype/truetype.c',
         'freetype/src/type1/type1.c',
         'freetype/src/cid/type1cid.c',
       ],
     },
     {
-      'target_name': 'safemath',
+      'target_name': 'pdfium_base',
       'type': 'none',
       'sources': [
-        'logging.h',
-        'macros.h',
-        'template_util.h',
-        'numerics/safe_conversions.h',
-        'numerics/safe_conversions_impl.h',
-        'numerics/safe_math.h',
-        'numerics/safe_math_impl.h',
+        'base/logging.h',
+        'base/macros.h',
+        'base/template_util.h',
+        'base/numerics/safe_conversions.h',
+        'base/numerics/safe_conversions_impl.h',
+        'base/numerics/safe_math.h',
+        'base/numerics/safe_math_impl.h',
       ],
     },
   ],
 }