Revert of mojo: make libmojo_public_test_support a static library.

mojo/mojo_public.gyp

Index: mojo/mojo_public.gyp
diff --git a/mojo/mojo_public.gyp b/mojo/mojo_public.gyp
index f6d306e081517d29e341e27cd6756ea9e6086246..2227d7651e40e5f93ff736e4c0a7aa86f652f4c4 100644
--- a/mojo/mojo_public.gyp
+++ b/mojo/mojo_public.gyp
@@ -331,7 +331,9 @@
     {
       # GN version: //mojo/public/c/test_support
       'target_name': 'mojo_public_test_support',
-      'type': 'static_library',
+      'defines': [
+        'MOJO_TEST_SUPPORT_IMPLEMENTATION',
+      ],
       'include_dirs': [
         '..',
       ],
@@ -342,9 +344,23 @@
       },
       'sources': [
         'public/c/test_support/test_support.h',
+        'public/c/test_support/test_support_export.h',
         # TODO(vtl): Convert this to thunks http://crbug.com/386799
         'public/tests/test_support_private.cc',
         'public/tests/test_support_private.h',
+      ],
+      'conditions': [
+        ['OS=="ios"', {
+          'type': 'static_library',
+        }, {
+          'type': 'shared_library',
+        }],
+        ['OS=="mac"', {
+          'xcode_settings': {
+            # Make it a run-path dependent library.
+            'DYLIB_INSTALL_NAME_BASE': '@loader_path',
+          },
+        }],
       ],
     },
     {