Integrate syzygy (optionally) into the chrome build process.

chrome/chrome_dll.gypi

 # Copyright (c) 2011 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.
 {
   'target_defaults': {
     'variables': {
       'chrome_dll_target': 0,
     },
     'target_conditions': [
       ['chrome_dll_target==1', {
@@ skipping 45 matching lines @@
             },
           }],  # OS=="win"
         ],  # conditions
       }],
     ],
   },
   'conditions': [
     ['OS=="mac" or OS=="win"', {
       'targets': [
         {
-          'target_name': 'chrome_dll',
-          'type': 'shared_library',
           'variables': {
             'chrome_dll_target': 1,
+            'conditions' : [
+              ['OS=="win"', {
+                # On Windows we use build chrome_dll as an intermediate target
+                # then have a subsequent step which either optimizes it to its
+                # final location, or copies it to its final location, depending
+                # on whether or not optimize_with_syzygy==1.  Please, refer to
+                # chrome_dll_syzygy.gypi for the subsequent defintion of the
+                # Windows chrome_dll target.
+                'dll_target_name': 'chrome_dll_initial',
+              }, {
+                'dll_target_name': 'chrome_dll',
+              }],
+            ],
           },
+          'target_name': '<(dll_target_name)',
+          'type': 'shared_library',
           'dependencies': [
             '<@(chromium_dependencies)',
             'app/policy/cloud_policy_codegen.gyp:policy',
           ],
           'conditions': [
             ['OS=="win"', {
               'product_name': 'chrome',
               'dependencies': [
                 # On Windows, link the dependencies (libraries) that make
                 # up actual Chromium functionality into this .dll.
@@ skipping 45 matching lines @@
                 '<(SHARED_INTERMEDIATE_DIR)/webkit/webkit_resources.rc',
 
                 # TODO(sgk):  left-over from pre-gyp build, figure out
                 # if we still need them and/or how to update to gyp.
                 #'app/check_dependents.bat',
                 #'app/chrome.dll.deps',
               ],
               'msvs_settings': {
                 'VCLinkerTool': {
                   'ImportLibrary': '$(OutDir)\\lib\\chrome_dll.lib',
-                  'ProgramDatabaseFile': '$(OutDir)\\chrome_dll.pdb',
+                  # On Windows we use build chrome_dll as an intermediate target
+                  # then have a subsequent step which either optimizes it to its
+                  # final location, or copies it to its final location, based
+                  # on whether or not optimize_with_syzygy==1.
+                  'ProgramDatabaseFile': '$(OutDir)\\initial\\chrome_dll.pdb',
+                  'OutputFile': '$(OutDir)\\initial\\chrome.dll',
+                  'conditions': [
+                    ['fastbuild==0', {
+                      # This corresponds to the /PROFILE flag which ensures the PDB
+                      # file contains FIXUP information. This information is used
+                      # by the Syzygy optimization tool. Syzygy optimization is
+                      # disabled when fastbuild!=0.
+                      'Profile': 'true',
+                    }],
+                  ],
                 },
               },
             }],  # OS=="win"
             ['OS=="mac"', {
               # The main browser executable's name is <(mac_product_name).
               # Certain things will get confused if two modules in the
               # executable share the same name, so append " Framework" to the
               # product_name used for the framework.  This will result in
               # a name like "Chromium Framework.framework".
               'product_name': '<(mac_product_name) Framework',
@@ skipping 565 matching lines @@
                   'LinkIncremental': '<(msvs_debug_link_nonincremental)',
                 },
               },
             },
           },
         },  # target chrome_dll
       ],
     }],
   ],
 }