Disable WPO for mini_installer

chrome/installer/mini_installer.gyp

 {
   'variables': {
     'version_py': '<(DEPTH)/build/util/version.py',
     'version_path': '../../chrome/VERSION',
     'lastchange_path': '<(DEPTH)/build/util/LASTCHANGE',
     # 'branding_dir' is set in the 'conditions' section at the bottom.
     'msvs_use_common_release': 0,
     'msvs_use_common_linker_extras': 0,
     'mini_installer_internal_deps%': 0,
     'mini_installer_official_deps%': 0,
@@ skipping 116 matching lines @@
               },
             },
             'Release_Base': {
               'includes': ['../../build/internal/release_defaults.gypi'],
               'msvs_settings': {
                 'VCCLCompilerTool': {
                   'EnableIntrinsicFunctions': 'true',
                   'BasicRuntimeChecks': '0',
                   'BufferSecurityCheck': 'false',
                   'ExceptionHandling': '0',
+                  'WholeProgramOptimization': 'false',
                 },
                 'VCLinkerTool': {
                   'SubSystem': '2',     # Set /SUBSYSTEM:WINDOWS
                   'Profile': 'false',   # Conflicts with /FIXED
                   'AdditionalOptions': [
                     '/SAFESEH:NO',
                     '/NXCOMPAT',
                     '/DYNAMICBASE:NO',
                     '/FIXED',
                   ],
@@ skipping 194 matching lines @@
       'variables': {
          'branding_dir': '../app/theme/google_chrome',
       },
     }, { # else branding!="Chrome"
       'variables': {
          'branding_dir': '../app/theme/chromium',
       },
     }],
   ],
 }