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

chrome/common/trace_event_args_whitelist.cc

Index: chrome/common/trace_event_args_whitelist.cc
diff --git a/chrome/common/trace_event_args_whitelist.cc b/chrome/common/trace_event_args_whitelist.cc
new file mode 100644
index 0000000000000000000000000000000000000000..cf1b4a98cd679c8a30d14834f00f3493155cd16f
--- /dev/null
+++ b/chrome/common/trace_event_args_whitelist.cc
@@ -0,0 +1,37 @@
+// 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.
+
+#include "chrome/common/trace_event_args_whitelist.h"
+
+#include "base/strings/string_tokenizer.h"
+#include "base/strings/string_util.h"
+
+namespace {
+
+const char* const kEventArgsWhitelist[][2] = {{"toplevel", "*"},

[dsinclair, 2015/06/01 14:56:09]

Do these get matched as exact matches or just contains matches? We have events
like "toplevel.flow" will those pass the filter or be rejected?

+                                              {"__metadata", "thread_name"},
+                                              {NULL, NULL}};
+
+}  // namespace
+
+bool IsTraceEventArgsWhitelisted(const char* category_group_name,
+                                 const char* event_name) {
+  base::CStringTokenizer category_group_tokens(
+      category_group_name, category_group_name + strlen(category_group_name),
+      ",");
+  while (category_group_tokens.GetNext()) {
+    const std::string& category_group_token = category_group_tokens.token();
+    for (int i = 0; kEventArgsWhitelist[i][0] != NULL; ++i) {
+      DCHECK(kEventArgsWhitelist[i][1]);
+
+      if (MatchPattern(category_group_token.c_str(),
+                       kEventArgsWhitelist[i][0]) &&
+          MatchPattern(event_name, kEventArgsWhitelist[i][1])) {
+        return true;
+      }
+    }
+  }
+
+  return false;
+}