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

content/browser/service_worker/service_worker_context_wrapper.cc

Index: content/browser/service_worker/service_worker_context_wrapper.cc
diff --git a/content/browser/service_worker/service_worker_context_wrapper.cc b/content/browser/service_worker/service_worker_context_wrapper.cc
index 9170b2456e6692056d1644fafe3278a33568e28c..1a3fa8f9464c2e9aafd3c22674e95de278f54484 100644
--- a/content/browser/service_worker/service_worker_context_wrapper.cc
+++ b/content/browser/service_worker/service_worker_context_wrapper.cc
@@ -5,9 +5,14 @@
 #include "content/browser/service_worker/service_worker_context_wrapper.h"
 
 #include <map>
+#include <set>
+#include <string>
+#include <vector>
 
 #include "base/barrier_closure.h"
+#include "base/bind.h"
 #include "base/files/file_path.h"
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "content/browser/fileapi/chrome_blob_storage_context.h"
@@ -17,6 +22,7 @@
 #include "content/browser/service_worker/service_worker_quota_client.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/browser/service_worker_context.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "storage/browser/blob/blob_storage_context.h"
 #include "storage/browser/quota/quota_manager_proxy.h"
@@ -24,6 +30,27 @@
 
 namespace content {
 
+namespace {
+
+typedef std::set<std::string> HeaderNameSet;
+base::LazyInstance<HeaderNameSet> g_excluded_header_name_set =
+    LAZY_INSTANCE_INITIALIZER;
+}
+
+void ServiceWorkerContext::AddExcludedHeadersForFetchEvent(
+    const std::vector<std::string>& header_names) {

[cbentzel, 2014/10/31 20:00:15]

Should this argument be a set rather than a vector given that this is ultimately
stored as a set and neither duplicates nor ordering really make sense?

Same for a few other locations in this changelist.

It's not a huge issue, so only do it if you think it's cleaner.

[horo, 2014/11/01 00:23:39]

Done.

+  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();
+}
+
 ServiceWorkerContextWrapper::ServiceWorkerContextWrapper(
     BrowserContext* browser_context)
     : observer_list_(