sync: remove use of protobuf extensions in protocol to reduce static init overhead.

chrome/browser/sync/syncable/syncable_unittest.cc

Index: chrome/browser/sync/syncable/syncable_unittest.cc
diff --git a/chrome/browser/sync/syncable/syncable_unittest.cc b/chrome/browser/sync/syncable/syncable_unittest.cc
index c2d9bd55d9ee542049510837e2b86c191ceb5e39..bf9ec3b26016e77e77a907cf99de26763d0cace5 100644
--- a/chrome/browser/sync/syncable/syncable_unittest.cc
+++ b/chrome/browser/sync/syncable/syncable_unittest.cc
@@ -62,9 +62,8 @@ void PutDataAsBookmarkFavicon(WriteTransaction* wtrans,
                               const char* bytes,
                               size_t bytes_length) {
   sync_pb::EntitySpecifics specifics;
-  specifics.MutableExtension(sync_pb::bookmark)->set_url("http://demo/");
-  specifics.MutableExtension(sync_pb::bookmark)->set_favicon(bytes,
-      bytes_length);
+  specifics.mutable_bookmark()->set_url("http://demo/");
+  specifics.mutable_bookmark()->set_favicon(bytes, bytes_length);
   e->Put(SPECIFICS, specifics);
 }
 
@@ -73,11 +72,10 @@ void ExpectDataFromBookmarkFaviconEquals(BaseTransaction* trans,
                                          const char* bytes,
                                          size_t bytes_length) {
   ASSERT_TRUE(e->good());
-  ASSERT_TRUE(e->Get(SPECIFICS).HasExtension(sync_pb::bookmark));
-  ASSERT_EQ("http://demo/",
-      e->Get(SPECIFICS).GetExtension(sync_pb::bookmark).url());
+  ASSERT_TRUE(e->Get(SPECIFICS).has_bookmark());
+  ASSERT_EQ("http://demo/", e->Get(SPECIFICS).bookmark().url());
   ASSERT_EQ(std::string(bytes, bytes_length),
-      e->Get(SPECIFICS).GetExtension(sync_pb::bookmark).favicon());
+            e->Get(SPECIFICS).bookmark().favicon());
 }
 }  // namespace
 
@@ -1201,8 +1199,8 @@ TEST_F(SyncableDirectoryTest, TestSimpleFieldsPreservedDuringSaveChanges) {
     create.Put(IS_UNSYNCED, true);
     update.Put(IS_UNAPPLIED_UPDATE, true);
     sync_pb::EntitySpecifics specifics;
-    specifics.MutableExtension(sync_pb::bookmark)->set_favicon("PNG");
-    specifics.MutableExtension(sync_pb::bookmark)->set_url("http://nowhere");
+    specifics.mutable_bookmark()->set_favicon("PNG");
+    specifics.mutable_bookmark()->set_url("http://nowhere");
     create.Put(SPECIFICS, specifics);
     create_pre_save = create.GetKernelCopy();
     update_pre_save = update.GetKernelCopy();