Extracted NetLog class's inner enum types into their own enum classes and

net/url_request/url_request_throttler_entry.cc

Index: net/url_request/url_request_throttler_entry.cc
diff --git a/net/url_request/url_request_throttler_entry.cc b/net/url_request/url_request_throttler_entry.cc
index 304d7d18465431b541ad7f53eea4de75f9bec40d..2bc7b6f15cd2c5f3fd1de0afae737e901ecda727 100644
--- a/net/url_request/url_request_throttler_entry.cc
+++ b/net/url_request/url_request_throttler_entry.cc
@@ -15,6 +15,8 @@
 #include "base/values.h"
 #include "net/base/load_flags.h"
 #include "net/log/net_log.h"
+#include "net/log/net_log_event_type.h"
+#include "net/log/net_log_source_type.h"
 #include "net/url_request/url_request.h"
 #include "net/url_request/url_request_context.h"
 #include "net/url_request/url_request_throttler_manager.h"
@@ -72,7 +74,8 @@ URLRequestThrottlerEntry::URLRequestThrottlerEntry(
       manager_(manager),
       url_id_(url_id),
       net_log_(BoundNetLog::Make(
-          manager->net_log(), NetLog::SOURCE_EXPONENTIAL_BACKOFF_THROTTLING)) {
+          manager->net_log(),
+          NetLogSourceType::EXPONENTIAL_BACKOFF_THROTTLING)) {
   DCHECK(manager_);
   Initialize();
 }
@@ -153,7 +156,7 @@ bool URLRequestThrottlerEntry::ShouldRejectRequest(
   if (!is_backoff_disabled_ && !ExplicitUserRequest(request.load_flags()) &&
       GetBackoffEntry()->ShouldRejectRequest()) {
     net_log_.AddEvent(
-        NetLog::TYPE_THROTTLING_REJECTED_REQUEST,
+        NetLogEventType::THROTTLING_REJECTED_REQUEST,
         base::Bind(&NetLogRejectedRequestCallback,
                    &url_id_,
                    GetBackoffEntry()->failure_count(),