Add creation of ServiceManager to Content (2nd try)

content/content_tests.gypi

Index: content/content_tests.gypi
diff --git a/content/content_tests.gypi b/content/content_tests.gypi
index 3eb88bea0f5101c4bde8e2670ee2818c1038babc..75109c36357f8616d2cf4d29aef79527047e3dd1 100644
--- a/content/content_tests.gypi
+++ b/content/content_tests.gypi
@@ -994,6 +994,7 @@
             'HAS_OUT_OF_PROC_TEST_RUNNER',
           ],
           'sources': [
+            'app/mojo/mojo_browsertest.cc',
             'browser/accessibility/accessibility_win_browsertest.cc',
             'browser/accessibility/cross_platform_accessibility_browsertest.cc',
             'browser/accessibility/dump_accessibility_tree_browsertest.cc',
@@ -1185,6 +1186,16 @@
                 ['exclude', '^browser/compositor/'],
               ],
             }],
+            ['use_mojo==1', {
+              'dependencies': [
+                '../mojo/mojo.gyp:mojo_environment_chromium',
+                '../mojo/mojo.gyp:mojo_service_manager',
+              ],
+            },{
+              'sources!': [
+                'app/mojo/mojo_browsertest.cc',
+              ],
+            }],
             ['OS!="android" and OS!="ios"', {
               # npapi test plugin doesn't build on android or ios
               'dependencies': [