Added a whitelist for trace events that are known to be PII-less.

content/common/trace_event_args_whitelist.h

Index: content/common/trace_event_args_whitelist.h
diff --git a/content/common/trace_event_args_whitelist.h b/content/common/trace_event_args_whitelist.h
new file mode 100644
index 0000000000000000000000000000000000000000..b40c4c141713eaf4aa1b2780642c81b98ec36843
--- /dev/null
+++ b/content/common/trace_event_args_whitelist.h
@@ -0,0 +1,18 @@
+// Copyright 2015 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.
+
+#ifndef CONTENT_COMMON_TRACING_CONSTANTS_INTERNAL_H_
+#define CONTENT_COMMON_TRACING_CONSTANTS_INTERNAL_H_
+
+#include "base/basictypes.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+CONTENT_EXPORT bool IsTraceEventArgsWhitelisted(const char* category_group_name,
+                                                const char* event_name);
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_TRACING_CONSTANTS_INTERNAL_H_