Enable XFA forms in the PDF plugin.

build/common.gypi

 # Copyright (c) 2012 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 869 matching lines @@
         }],
 
         # Whether PDF plugin is enabled, and which options it supports.
         ['OS=="android" or OS=="ios" or (embedded==1 and chromecast==0)', {
           'enable_pdf%': 0,
           'pdf_enable_v8%': 0,
         }, {
           'enable_pdf%': 1,
           'pdf_enable_v8%': 1,
         }],
-        ['chromeos==1 or OS=="android" or OS=="ios" or (embedded==1 and chromecast==0)', {
+        ['OS=="android" or OS=="ios" or (embedded==1 and chromecast==0)', {
           'pdf_enable_xfa%': 0,
         }, {
-          'pdf_enable_xfa%': 0, # Reverted pending crbug.com/596373
+          'pdf_enable_xfa%': 1,
         }],
 
         ['chromeos==1 or OS=="android" or OS=="ios" or desktop_linux==1', {
           'enable_plugin_installation%': 0,
         }, {
           'enable_plugin_installation%': 1,
         }],
 
         # Whether PPAPI is enabled.
         ['OS=="android" or OS=="ios" or (embedded==1 and chromecast==0)', {
@@ skipping 5408 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }