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

components/variations/variations_http_header_provider.cc

Index: components/variations/variations_http_header_provider.cc
diff --git a/components/variations/variations_http_header_provider.cc b/components/variations/variations_http_header_provider.cc
index 12d9c9f4e365aafcae659da51fbfadf451314ce8..0038d4b9c9a38d1242ab568c6d59e92e9ced89d2 100644
--- a/components/variations/variations_http_header_provider.cc
+++ b/components/variations/variations_http_header_provider.cc
@@ -36,6 +36,10 @@ const char* kSuffixesToSetHeadersFor[] = {
   ".ytimg.com",
 };
 
+// Keep in sync with service_worker_url_request_job.cc.
+const char kChromeUMAEnabled[] = "X-Chrome-UMA-Enabled";
+const char kClientData[] = "X-Client-Data";
+
 }  // namespace
 
 VariationsHttpHeaderProvider* VariationsHttpHeaderProvider::GetInstance() {
@@ -61,7 +65,7 @@ void VariationsHttpHeaderProvider::AppendHeaders(
     return;
 
   if (uma_enabled)
-    headers->SetHeaderIfMissing("X-Chrome-UMA-Enabled", "1");
+    headers->SetHeaderIfMissing(kChromeUMAEnabled, "1");
 
   // Lazily initialize the header, if not already done, before attempting to
   // transmit it.
@@ -75,8 +79,7 @@ void VariationsHttpHeaderProvider::AppendHeaders(
 
   if (!variation_ids_header_copy.empty()) {
     // Note that prior to M33 this header was named X-Chrome-Variations.
-    headers->SetHeaderIfMissing("X-Client-Data",
-                                variation_ids_header_copy);
+    headers->SetHeaderIfMissing(kClientData, variation_ids_header_copy);
   }
 }