[Sync] Add sync_export.h (Step 1 for componentizing sync)

chrome/chrome_tests.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.
 {
   'variables' : {
     'pyautolib_sources': [
       'app/chrome_command_ids.h',
       'app/chrome_dll_resource.h',
       'common/automation_constants.h',
       'common/pref_names.cc',
@@ skipping 922 matching lines @@
                 },
               },
             },
           },
         }],
       ],
     },
     {
       'target_name': 'unit_tests',
       'type': 'executable',
+      'defines': [
+        'SYNC_TEST',
+      ],
       'dependencies': [
         # unit tests should only depend on
         # 1) everything that the chrome binaries depend on:
         '<@(chromium_dependencies)',
         # 2) test-specific support libraries:
         '../base/base.gyp:test_support_base',
         '../gpu/gpu.gyp:gpu_unittest_utils',
         '../media/media.gyp:media_test_support',
         '../net/net.gyp:net',
         '../net/net.gyp:net_test_support',
@@ skipping 2891 matching lines @@
           'destination': '<(PRODUCT_DIR)/test/data/third_party/kraken/hosted/kraken-1.1',
           'files': [
             'test/perf/kraken_benchmark_uitest.js',
           ],
         },
       ],
     },
     {
       'target_name': 'sync_integration_tests',
       'type': 'executable',
+      'defines': [
+        'SYNC_TEST',
+      ],
       'dependencies': [
         'browser',
         '../sync/protocol/sync_proto.gyp:sync_proto',
         'chrome',
         'chrome_resources.gyp:chrome_resources',
         'chrome_resources.gyp:chrome_strings',
         'common',
         'renderer',
         'test_support_common',
         '../net/net.gyp:net',
@@ skipping 144 matching lines @@
         ['toolkit_views==1', {
           'dependencies': [
             '../ui/views/views.gyp:views',
           ],
         }],
       ],
     },
     {
       'target_name': 'sync_performance_tests',
       'type': 'executable',
+      'defines': [
+        'SYNC_TEST',
+      ],
       'dependencies': [
         '../sync/protocol/sync_proto.gyp:sync_proto',
         'browser',
         'chrome',
         'test_support_common',
         '../skia/skia.gyp:skia',
         '../testing/gmock.gyp:gmock',
         '../testing/gtest.gyp:gtest',
       ],
       'include_dirs': [
@@ skipping 637 matching lines @@
               # Use outputs of this action as inputs for the main target build.
               # Seems as a misnomer but makes this happy on Linux (scons).
               'process_outputs_as_sources': 1,
             },
           ],  # 'actions'
         },
       ]
     }],  # 'coverage!=0'
   ],  # 'conditions'
 }