Add PGO targets to Chrome.

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 1069 matching lines @@
     '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 setting to break chrome.dll into multiple pieces based on
     # process type.
     'chrome_multiple_dll%': '0',
 
+    # Experimental setting to optimize Chrome's DLL with PGO.
+    'chrome_pgo%': '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',
 
     # Clang stuff.
     'clang%': '<(clang)',
@@ skipping 3429 matching lines @@
               # In official builds, targets can self-select an optimization
               # level by defining a variable named 'optimize', and setting it
               # to one of
               # - "size", optimizes for minimal code size - the default.
               # - "speed", optimizes for speed over code size.
               # - "max", whole program optimization and link-time code
               #   generation. This is very expensive and should be used
               #   sparingly.
               'variables': {
                 'optimize%': 'size',
+                'ltcg_value%': '1',
               },
               'target_conditions': [
                 ['optimize=="size"', {
                     'msvs_settings': {
                       'VCCLCompilerTool': {
                         # 1, optimizeMinSpace, Minimize Size (/O1)
                         'Optimization': '1',
                         # 2, favorSize - Favor small code (/Os)
                         'FavorSizeOrSpeed': '2',
                       },
@@ skipping 481 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',
   },
 }