Allow targets to self-select optimization level in official builds.

build/internal/release_impl_official.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.
 {
   'includes': ['release_defaults.gypi'],
   'defines': ['OFFICIAL_BUILD'],
   'msvs_settings': {
     'VCCLCompilerTool': {
       'Optimization': '3',
       'InlineFunctionExpansion': '2',
       'EnableIntrinsicFunctions': 'true',
       'FavorSizeOrSpeed': '2',
       'OmitFramePointers': 'true',
       'EnableFiberSafeOptimizations': 'true',
-      'WholeProgramOptimization': 'true',
     },
     'VCLibrarianTool': {
-      'AdditionalOptions': ['/ltcg', '/expectedoutputsize:120000000'],
+      'AdditionalOptions': [
+        '/ltcg',
+        '/expectedoutputsize:120000000'
+      ],
     },
     'VCLinkerTool': {

[bradn, 2011/12/16 23:44:45]

How about using target_conditions to inject this instead.
'target_defaults': [
  'variables': {
    'performance_critical%': 0,
  },
  'target_conditions': [
    'performance_critical==1', {
      'msvs_settings': {
        'VCCLCompilerTool': {'WholeProgramOptimization': 'true'},
     },
    },
  ],

Then each target can just add:
'performance_critical': 1, to the variable section or each target (or each
target_defaults in a gyp).
Two advantages:
- a clear way to inject into all the targets in a gyp file.
- no specific pathing to an include (allowing us to change things round).

-      # Get more debug spew from the linker while we're sorting out
-      # build problems and performance.
-      # TODO(siggi): Remove these flags after we're out of the woods.
       'AdditionalOptions': [
         '/time',
         # This may reduce memory fragmentation during linking.
         # The expected size is 40*1024*1024, which gives us about 10M of
         # headroom as of Dec 16, 2011.
         '/expectedoutputsize:41943040',
       ],
       'LinkTimeCodeGeneration': '1',
       # The /PROFILE flag causes the linker to add a "FIXUP" debug stream to
       # the generated PDB. According to MSDN documentation, this flag is only
       # available (or perhaps supported) in the Enterprise (team development)
       # version of Visual Studio. If this blocks your official build, simply
       # comment out this line, then  re-run "gclient runhooks".
       'Profile': 'true',
     },
   },
 }