Apply NIK to reporting and NEL, part 1.

Add NIK to the on-disk reporting and NEL information.

Bug: 993805
Change-Id: I27b1242458e48423b7615effcee3de5afda916e9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2485253Reviewed-by: Lily Chen <chlily@chromium.org>
Commit-Queue: Matt Menke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#819056}

net/network_error_logging/network_error_logging_service.h

@@ -18,6 +18,7 @@
 #include "net/base/ip_address.h"
 #include "net/base/net_errors.h"
 #include "net/base/net_export.h"
+#include "net/base/network_isolation_key.h"
 #include "url/gurl.h"
 #include "url/origin.h"
 
@@ -49,6 +50,10 @@ class NET_EXPORT NetworkErrorLoggingService {
     NelPolicy(const NelPolicy& other);
     ~NelPolicy();
 
+    // TODO(mmenke): Actually populate this field. Currently only used by the
+    // persistence layer.
+    NetworkIsolationKey network_isolation_key = NetworkIsolationKey::Todo();
+
     url::Origin origin;
     IPAddress received_ip_address = IPAddress();