[ServiceWorker] Don't send the UMA related headers to the ServiceWorker.

content/public/browser/service_worker_context.cc

+// Copyright 2014 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 "content/public/browser/service_worker_context.h"
+
+#include "base/bind.h"
+#include "base/lazy_instance.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace content {
+
+namespace {
+
+typedef std::set<std::string> HeaderNameSet;
+static base::LazyInstance<HeaderNameSet> g_excluded_header_name_set =
+    LAZY_INSTANCE_INITIALIZER;
+}
+
+void ServiceWorkerContext::AddExcludedHeadersForFetchEvent(
+    const std::vector<std::string> header_names) {
+  if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
+    BrowserThread::PostTask(
+        BrowserThread::IO,
+        FROM_HERE,
+        base::Bind(ServiceWorkerContext::AddExcludedHeadersForFetchEvent,
+                   header_names));
+    return;
+  }
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  g_excluded_header_name_set.Get().insert(header_names.begin(),
+                                          header_names.end());
+}
+
+bool ServiceWorkerContext::IsExcludedHeaderNameForFetchEvent(
+    const std::string& header_name) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  return g_excluded_header_name_set.Get().find(header_name) !=
+         g_excluded_header_name_set.Get().end();
+}
+
+}  // namespace content