[Sync] Implement MemoryDumpProvider.

components/sync/syncable/directory_backing_store.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/sync/syncable/directory_backing_store.h"
 
 #include <stddef.h>
 
 #include <limits>
 #include <unordered_set>
@@ skipping 1700 matching lines @@
 
 // Get page size for the database.
 bool DirectoryBackingStore::GetDatabasePageSize(int* page_size) {
   sql::Statement s(db_->GetUniqueStatement("PRAGMA page_size"));
   if (!s.Step())
     return false;
   *page_size = s.ColumnInt(0);
   return true;
 }
 
+bool DirectoryBackingStore::ReportMemoryUsage(
+    base::trace_event::MemoryAllocatorDump* mad) {
+  return db_ && db_->ReportMemoryUsage(mad);
+}
+
 bool DirectoryBackingStore::UpdatePageSizeIfNecessary() {
   int page_size;
   if (!GetDatabasePageSize(&page_size))
     return false;
   if (page_size == kCurrentPageSizeKB)
     return true;
   std::string update_page_size = base::StringPrintf(
     "PRAGMA page_size=%i;", kCurrentPageSizeKB);
   if (!db_->Execute(update_page_size.c_str()) || !Vacuum())
     return false;
@@ skipping 31 matching lines @@
   DCHECK(CalledOnValidThread());
   DCHECK(!catastrophic_error_handler.is_null());
   catastrophic_error_handler_ = catastrophic_error_handler;
   sql::Connection::ErrorCallback error_callback =
       base::Bind(&OnSqliteError, catastrophic_error_handler_);
   db_->set_error_callback(error_callback);
 }
 
 }  // namespace syncable
 }  // namespace syncer