Add chrome_split_dll gyp variable, and duplicate chrome_main_dll target

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 875 matching lines @@
     # but that doesn't work as we'd like.
     'msvs_debug_link_incremental%': '2',
 
     # Needed for some of the largest modules.
     'msvs_debug_link_nonincremental%': '1',
 
     # Turns on Use Library Dependency Inputs for linking chrome.dll on Windows
     # to get incremental linking to be faster in debug builds.
     'incremental_chrome_dll%': '0',
 
+    # Experimental split of chrome.dll into two separate subparts on Windows.
+    'chrome_split_dll%': '0',
+
     # The default settings for third party code for treating
     # warnings-as-errors. Ideally, this would not be required, however there
     # is some third party code that takes a long time to fix/roll. So, this
     # flag allows us to have warnings as errors in general to prevent
     # regressions in most modules, while working on the bits that are
     # remaining.
     'win_third_party_warn_as_error%': 'true',
 
     # This is the location of the sandbox binary. Chrome looks for this before
     # running the zygote process. If found, and SUID, it will be used to
@@ skipping 3457 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',
   },
 }