[Sync] Eliminate friends from Directory by exposing kernel via accessor

sync/syncable/mutable_entry.cc

Index: sync/syncable/mutable_entry.cc
diff --git a/sync/syncable/mutable_entry.cc b/sync/syncable/mutable_entry.cc
index f6f3f16c7196fb1590616093420945769d001ba1..0b5ee552bc767707061d7d2fe739e847240500c2 100644
--- a/sync/syncable/mutable_entry.cc
+++ b/sync/syncable/mutable_entry.cc
@@ -28,7 +28,7 @@ void MutableEntry::Init(WriteTransaction* trans,
 
   kernel->put(ID, trans->directory_->NextId());
   kernel->put(META_HANDLE, trans->directory_->NextMetahandle());
-  kernel->mark_dirty(&trans->directory_->kernel_->dirty_metahandles);
+  kernel->mark_dirty(&trans->directory_->kernel()->dirty_metahandles);
   kernel->put(NON_UNIQUE_NAME, name);
   const base::Time& now = base::Time::Now();
   kernel->put(CTIME, now);
@@ -126,7 +126,7 @@ void MutableEntry::PutLocalExternalId(int64 value) {
   if (kernel_->ref(LOCAL_EXTERNAL_ID) != value) {
     ScopedKernelLock lock(dir());
     kernel_->put(LOCAL_EXTERNAL_ID, value);
-    kernel_->mark_dirty(&dir()->kernel_->dirty_metahandles);
+    kernel_->mark_dirty(&dir()->kernel()->dirty_metahandles);
   }
 }
 
@@ -135,7 +135,7 @@ void MutableEntry::PutMtime(base::Time value) {
   write_transaction()->TrackChangesTo(kernel_);
   if (kernel_->ref(MTIME) != value) {
     kernel_->put(MTIME, value);
-    kernel_->mark_dirty(&dir()->kernel_->dirty_metahandles);
+    kernel_->mark_dirty(&dir()->kernel()->dirty_metahandles);
   }
 }
 
@@ -144,7 +144,7 @@ void MutableEntry::PutCtime(base::Time value) {
   write_transaction()->TrackChangesTo(kernel_);
   if (kernel_->ref(CTIME) != value) {
     kernel_->put(CTIME, value);
-    kernel_->mark_dirty(&dir()->kernel_->dirty_metahandles);
+    kernel_->mark_dirty(&dir()->kernel()->dirty_metahandles);
   }
 }
 
@@ -199,10 +199,10 @@ void MutableEntry::PutIsDel(bool value) {
     // Some indices don't include deleted items and must be updated
     // upon a value change.
     ScopedParentChildIndexUpdater updater(lock, kernel_,
-        &dir()->kernel_->parent_child_index);
+        &dir()->kernel()->parent_child_index);
 
     kernel_->put(IS_DEL, value);
-    kernel_->mark_dirty(&dir()->kernel_->dirty_metahandles);
+    kernel_->mark_dirty(&dir()->kernel()->dirty_metahandles);
   }
 }
 
@@ -212,7 +212,7 @@ void MutableEntry::PutNonUniqueName(const std::string& value) {
 
   if (kernel_->ref(NON_UNIQUE_NAME) != value) {
     kernel_->put(NON_UNIQUE_NAME, value);
-    kernel_->mark_dirty(&dir()->kernel_->dirty_metahandles);
+    kernel_->mark_dirty(&dir()->kernel()->dirty_metahandles);
   }
 }
 
@@ -225,7 +225,7 @@ void MutableEntry::PutSpecifics(const sync_pb::EntitySpecifics& value) {
   if (kernel_->ref(SPECIFICS).SerializeAsString() !=
       value.SerializeAsString()) {
     kernel_->put(SPECIFICS, value);
-    kernel_->mark_dirty(&dir()->kernel_->dirty_metahandles);
+    kernel_->mark_dirty(&dir()->kernel()->dirty_metahandles);
   }
 }
 
@@ -237,9 +237,9 @@ void MutableEntry::PutUniquePosition(const UniquePosition& value) {
     DCHECK(value.IsValid());
     ScopedKernelLock lock(dir());
     ScopedParentChildIndexUpdater updater(
-        lock, kernel_, &dir()->kernel_->parent_child_index);
+        lock, kernel_, &dir()->kernel()->parent_child_index);
     kernel_->put(UNIQUE_POSITION, value);
-    kernel_->mark_dirty(&dir()->kernel_->dirty_metahandles);
+    kernel_->mark_dirty(&dir()->kernel()->dirty_metahandles);
   }
 }
 
@@ -265,7 +265,7 @@ void MutableEntry::PutAttachmentMetadata(
                                  kernel_->ref(ATTACHMENT_METADATA),
                                  attachment_metadata);
     kernel_->put(ATTACHMENT_METADATA, attachment_metadata);
-    kernel_->mark_dirty(&dir()->kernel_->dirty_metahandles);
+    kernel_->mark_dirty(&dir()->kernel()->dirty_metahandles);
   }
 }
 
@@ -283,7 +283,7 @@ void MutableEntry::MarkAttachmentAsOnServer(
       continue;
     record->set_is_on_server(true);
   }
-  kernel_->mark_dirty(&dir()->kernel_->dirty_metahandles);
+  kernel_->mark_dirty(&dir()->kernel()->dirty_metahandles);
   MarkForSyncing(this);
 }