Rename methods and members and const variables to alternative service.

Rename methods and members and const variables from "alternate protocol" to
"alternative service":

* alternate_protocol_probability_threshold_ to
  alternative_service_probability_threshold_ in HttpServerPropertiesImpl,
* switches::kAlternateProtocolProbabilityThreshold to
  switches::kAlternativeServiceProbabilityThreshold,
* test names in IOThreadTest,
* SetAlternateProtocolProbabilityThreshold() to
  SetAlternativeServiceProbabilityThreshold(),
* GetAlternateProtocolProbabilityThreshold() to
  GetAlternativeServiceProbabilityThreshold(),
* remove obsolete force-alt-protocols from comments in io_thread.cc,
* "Alternate Protocol" to "Alternative Service" in NetInternals user facing
  QUIC page,
* alternate_protocol_probability_threshold to
  alternative_service_probability_threshold in IOThread::Globals and
  HttpNetworkSession::Params.

BUG=392575

Review URL: https://codereview.chromium.org/1091283007

Cr-Commit-Position: refs/heads/master@{#327038}
diff --git a/net/quic/quic_network_transaction_unittest.cc b/net/quic/quic_network_transaction_unittest.cc
index 6142070..f02d8118 100644
--- a/net/quic/quic_network_transaction_unittest.cc
+++ b/net/quic/quic_network_transaction_unittest.cc
@@ -663,7 +663,7 @@
   // the alternate-protocol job will "win".
   AddHangingNonAlternateProtocolSocketData();
 
-  params_.alternate_protocol_probability_threshold = .25;
+  params_.alternative_service_probability_threshold = .25;
   CreateSessionWithNextProtos();
 
   SendRequestAndExpectHttpResponse("hello world");
@@ -684,7 +684,7 @@
   socket_factory_.AddSocketDataProvider(&http_data);
   socket_factory_.AddSocketDataProvider(&http_data);
 
-  params_.alternate_protocol_probability_threshold = .75;
+  params_.alternative_service_probability_threshold = .75;
   CreateSessionWithNextProtos();
 
   SendRequestAndExpectHttpResponse("hello world");
@@ -706,7 +706,7 @@
   socket_factory_.AddSocketDataProvider(&http_data);
   socket_factory_.AddSocketDataProvider(&http_data);
 
-  params_.alternate_protocol_probability_threshold = .75;
+  params_.alternative_service_probability_threshold = .75;
   CreateSessionWithNextProtos();
 
   SendRequestAndExpectHttpResponse("hello world");