Delete ExpectCTState::domain.

It's not actually being used anywhere.

Bug: None
Change-Id: Id11dddbbc99d78de841a2faafe2473adbbee197d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2216284Reviewed-by: Emily Stark <estark@chromium.org>
Commit-Queue: Matt Menke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#772111}

net/http/transport_security_state.cc

@@ -823,7 +823,6 @@ bool TransportSecurityState::GetStaticExpectCTState(
   if (!enable_static_expect_ct_ || !result.expect_ct)
     return false;
 
-  expect_ct_state->domain = host.substr(result.hostname_offset);
   expect_ct_state->report_uri = GURL(
       g_hsts_source->expect_ct_report_uris[result.expect_ct_report_uri_id]);
   return true;

net/http/transport_security_state.h

@@ -232,8 +232,6 @@ class NET_EXPORT TransportSecurityState {
     ExpectCTState();
     ~ExpectCTState();
 
-    // The domain which matched during a search for this DomainState entry.
-    std::string domain;
     // The URI to which reports should be sent if valid CT info is not
     // provided.
     GURL report_uri;

net/http/transport_security_state_unittest.cc

@@ -940,7 +940,6 @@ TEST_F(TransportSecurityStateTest, PreloadedExpectCT) {
   TransportSecurityState::ExpectCTState expect_ct_state;
   EXPECT_TRUE(
       GetExpectCTState(&state, kExpectCTStaticHostname, &expect_ct_state));
-  EXPECT_EQ(kExpectCTStaticHostname, expect_ct_state.domain);
   EXPECT_EQ(GURL(kExpectCTStaticReportURI), expect_ct_state.report_uri);
   EXPECT_FALSE(
       GetExpectCTState(&state, "hsts-preloaded.test", &expect_ct_state));