Add unit_tests_run that (mostly) works for all of linux, OSX and Windows.

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 2580 matching lines @@
                   # linking errors on 64-bit bots too. http://crbug.com/52555
                   'LinkIncremental': '1',
                 },
               },
             },
           },
         }],
       ],
     },
     {
+      'target_name': 'unit_tests_run',
+      'type': 'none',
+      'dependencies': [
+        'unit_tests',
+      ],
+      'includes': [
+        'unit_tests.isolate',
+      ],
+      'actions': [
+        {
+          'action_name': 'isolate',
+          'inputs': [
+            '<@(isolate_dependency_tracked)',
+          ],
+          'outputs': [
+            '<(PRODUCT_DIR)/unit_tests.results',
+          ],
+          'action': [
+            'python',
+            '../tools/isolate/isolate.py',
+            '--mode', '<(tests_run)',
+            '--variable', 'PRODUCT_DIR', '<(PRODUCT_DIR)',
+            '--variable', 'OS', '<(OS)',
+            '--result', '<@(_outputs)',
+            'unit_tests.isolate',
+          ],
+        },
+      ],
+    },
+    {
       # Executable that runs each browser test in a new process.
       'target_name': 'browser_tests',
       'type': 'executable',
       'msvs_cygwin_shell': 0,
       'msvs_cygwin_dirs': ['<(DEPTH)/third_party/cygwin'],
       'copies': [
         {
           'destination': '<(PRODUCT_DIR)',
           'files': [
             # Keep 'test_case.html.mock-http-headers' with 'test_case.html'.
@@ skipping 2031 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'
 }