First pass at content shell for the Mac. Doesn't work yet.

chrome/chrome_dll.gypi

Index: chrome/chrome_dll.gypi
diff --git a/chrome/chrome_dll.gypi b/chrome/chrome_dll.gypi
index afd6034465b9e5d6396f1c1c68842526b95aa49c..f3b3fe27e534a4de050a9dba270eb70bf7442064 100644
--- a/chrome/chrome_dll.gypi
+++ b/chrome/chrome_dll.gypi
@@ -204,6 +204,9 @@
                 # Define the order of symbols within the framework.  This
                 # sets -order_file.
                 'ORDER_FILE': 'app/framework.order',
+
+                # Hide symbols that shouldn't be exported.
+                'UNEXPORTED_SYMBOLS_FILE': 'app/unexported_symbols.exp',
               },
               'sources': [
                 'app/chrome_command_ids.h',
@@ -508,7 +511,7 @@
                     {
                       'postbuild_name': 'Copy KeystoneRegistration.framework',
                       'action': [
-                        'tools/build/mac/copy_framework_unversioned',
+                        '../build/mac/copy_framework_unversioned',
                         '../third_party/googlemac/Releases/Keystone/KeystoneRegistration.framework',
                         '${BUILT_PRODUCTS_DIR}/${CONTENTS_FOLDER_PATH}/Frameworks',
                       ],