Add support for building with goma.

build/standalone.gypi

 # Copyright 2014 PDFium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Definitions to be used when building stand-alone PDFium binaries.
 
 {
   'variables': {
     'component%': 'static_library',
     'clang%': 0,
     'asan%': 0,
     'sanitizer_coverage%': 0,
+    'use_goma%': 0,
+    'gomadir%': '',
     'msvs_multi_core_compile%': '1',
     'variables': {
       'variables': {
         'variables': {
           'conditions': [
             ['OS=="linux" or OS=="mac"', {
               # This handles the Unix platforms we generally deal with.
               # Anything else gets passed through, which probably won't work
               # very well; such hosts should pass an explicit target_arch
               # to gyp.
@@ skipping 28 matching lines @@
       ['OS == "win"', {
         'os_posix%': 0,
       }, {
         'os_posix%': 1,
       }],
       ['OS=="linux" or OS=="mac"', {
         'clang%': 1,
       }, {
         'clang%': 0,
       }],
+      # Set default gomadir.
+      ['OS=="win"', {
+        'gomadir%': 'c:\\goma\\goma-win',
+      }, {
+        'gomadir%': '<!(/bin/echo -n ${HOME}/goma)',
+      }],
     ],
   },
   'target_defaults': {
     'default_configuration': 'Debug',
     'configurations': {
       'Debug': {
         'cflags': [
           '-g',
           '-O0',
           '-fdata-sections',
@@ skipping 205 matching lines @@
           'NOMINMAX',
           '_CRT_SECURE_NO_DEPRECATE',
           '_CRT_NONSTDC_NO_DEPRECATE',
         ],
         'conditions': [
           ['component=="static_library"', {
             'defines': [
               '_HAS_EXCEPTIONS=0',
             ],
           }],
+          ['use_goma==1', {
+            # goma doesn't support PDB yet.
+            'msvs_settings': {
+              'VCLinkerTool': {
+                'GenerateDebugInformation': 'true',
+              },
+              'VCCLCompilerTool': {
+                'DebugInformationFormat': '1',
+              },
+            },
+          }],
         ],
       }],  # OS=="win"
       ['OS=="mac"', {
         'target_conditions': [
           ['_type!="static_library"', {
             'xcode_settings': {'OTHER_LDFLAGS': ['-Wl,-search_paths_first']},
           }],
         ],  # target_conditions
       }],  # OS=="mac"
       ['v8_use_external_startup_data==1', {
@@ skipping 11 matching lines @@
     ['OS=="linux" or OS=="mac"', {
       'conditions': [
         ['clang==1', {
           'make_global_settings': [
             ['CC', '<(clang_dir)/bin/clang'],
             ['CXX', '<(clang_dir)/bin/clang++'],
           ],
         }],
       ],
     }],  # OS=="linux" or OS=="mac"
+    ["use_goma==1", {
+      'make_global_settings': [
+        ['CC_wrapper', '<(gomadir)/gomacc'],
+        ['CXX_wrapper', '<(gomadir)/gomacc'],
+      ],
+    }],  # use_goma==1
   ],
 }