Pull necessary dependencies to be able to process mojo.gyp on iOS

mojo/mojo_base.gyp

Index: mojo/mojo_base.gyp
diff --git a/mojo/mojo_base.gyp b/mojo/mojo_base.gyp
index 1104ff935c211b2eb551edefd81ee0fab2e57488..62ff9690293323c3296fd426a8b213f250fc74d0 100644
--- a/mojo/mojo_base.gyp
+++ b/mojo/mojo_base.gyp
@@ -223,6 +223,14 @@
         'system/waiter_test_utils.h',
         'system/waiter_unittest.cc',
       ],
+      'conditions': [
+        ['OS=="ios"', {
+          'sources!': [
+            'embedder/embedder_unittest.cc',
+            'system/multiprocess_message_pipe_unittest.cc',
+          ],
+        }],
+      ],
     },
     {
       # GN version: //mojo/common/test:test_support_impl
@@ -283,6 +291,13 @@
         'common/test/test_utils_posix.cc',
         'common/test/test_utils_win.cc',
       ],
+      'conditions': [
+        ['OS=="ios"', {
+          'sources!': [
+            'common/test/multiprocess_test_helper.cc',
+          ],
+        }],
+      ],
     },
     {
       # GN version: //mojo/common:mojo_common_unittests
@@ -306,6 +321,13 @@
         'common/message_pump_mojo_unittest.cc',
         'common/test/multiprocess_test_helper_unittest.cc',
       ],
+      'conditions': [
+        ['OS=="ios"', {
+          'sources!': [
+            'common/test/multiprocess_test_helper_unittest.cc',
+          ],
+        }],
+      ],
     },
     {
       # GN version: //mojo/environment:chromium