Makes a handful of DataSources not replace the existing

chrome/browser/webui/chrome_url_data_manager_backend.cc

Index: chrome/browser/webui/chrome_url_data_manager_backend.cc
diff --git a/chrome/browser/webui/chrome_url_data_manager_backend.cc b/chrome/browser/webui/chrome_url_data_manager_backend.cc
index e484a052909d48530f5aa0a1d9f7df2bf21c6418..1f3d73bc874390ab887248f2b85f4bb904c63baa 100644
--- a/chrome/browser/webui/chrome_url_data_manager_backend.cc
+++ b/chrome/browser/webui/chrome_url_data_manager_backend.cc
@@ -178,8 +178,11 @@ void ChromeURLDataManagerBackend::AddDataSource(
     ChromeURLDataManager::DataSource* source) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   DataSourceMap::iterator i = data_sources_.find(source->source_name());
-  if (i != data_sources_.end())
+  if (i != data_sources_.end()) {
+    if (!source->ShouldReplaceExistingSource())
+      return;
     i->second->backend_ = NULL;
+  }
   data_sources_[source->source_name()] = source;
   source->backend_ = this;
 }