[Nearby] Messaging: Fix receive metric emission; add OAuth token metric

1. Only emit the receive-message metrics and logs if the callback has
   not already been invoked.
2. Record a fast-path-ready notification as a receive-message success.
3. Clarify receive-message histogram summaries to indicate that the
   metric records the result of opening the receive stream, i.e.,
   starting to receive messages, not a result for every message receipt.
4. Add metrics and logs to track send- and receive-message OAuth token
   fetches.

Manually verified logs and histograms.

Fixed: 1164009
Change-Id: I2a064cae444ec890971db40b15c93c713e32565c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2619628
Commit-Queue: Josh Nohle <nohle@chromium.org>
Reviewed-by: James Vecore <vecore@google.com>
Reviewed-by: Caitlin Fischer <caitlinfischer@google.com>
Reviewed-by: Ryan Hansberry <hansberry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842617}

chrome/browser/nearby_sharing/instantmessaging/receive_messages_express.cc

@@ -70,13 +70,12 @@ void LogReceiveResult(bool success, const network::SimpleURLLoader* loader) {
           "FailureReason",
           http_status.GetResultCodeForMetrics());
     }
-  } else {
-    ss << " Missing URL loader.";
   }
+
   if (success) {
     NS_LOG(VERBOSE) << ss.str();
   } else {
-    NS_LOG(WARNING) << ss.str();
+    NS_LOG(ERROR) << ss.str();
   }
 }
 
@@ -124,7 +123,12 @@ void ReceiveMessagesExpress::DoStartReceivingMessages(
         ReceiveMessagesExpressRequest& request,
     const std::string& oauth_token) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
+  base::UmaHistogramBoolean(
+      "Nearby.Connections.InstantMessaging.ReceiveExpress."
+      "OAuthTokenFetchResult",
+      !oauth_token.empty());
   if (oauth_token.empty()) {
+    NS_LOG(ERROR) << __func__ << ": Failed to fetch OAuth token.";
     std::move(success_callback_).Run(false);
     return;
   }
@@ -164,9 +168,10 @@ void ReceiveMessagesExpress::OnDataReceived(base::StringPiece data,
 
 void ReceiveMessagesExpress::OnComplete(bool success) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
-  LogReceiveResult(success, url_loader_.get());
-  if (!success_callback_.is_null())
+  if (!success_callback_.is_null()) {
+    LogReceiveResult(success, url_loader_.get());
     std::move(success_callback_).Run(success);
+  }
 
   url_loader_.reset();
   stream_parser_.reset();
@@ -178,6 +183,7 @@ void ReceiveMessagesExpress::OnRetry(base::OnceClosure start_retry) {
 
 void ReceiveMessagesExpress::OnFastPathReady() {
   if (!success_callback_.is_null()) {
+    LogReceiveResult(/*success=*/true, /*loader=*/nullptr);
     std::move(success_callback_).Run(true);
   }
 }

chrome/browser/nearby_sharing/instantmessaging/send_message_express.cc

@@ -63,7 +63,7 @@ void LogSendResult(bool success, const NearbyShareHttpStatus& http_status) {
   if (success) {
     NS_LOG(VERBOSE) << ss.str();
   } else {
-    NS_LOG(WARNING) << ss.str();
+    NS_LOG(ERROR) << ss.str();
   }
   base::UmaHistogramBoolean(
       "Nearby.Connections.InstantMessaging.SendExpress.Result", success);
@@ -100,7 +100,11 @@ void SendMessageExpress::DoSendMessage(
         SendMessageExpressRequest& request,
     SuccessCallback callback,
     const std::string& oauth_token) {
+  base::UmaHistogramBoolean(
+      "Nearby.Connections.InstantMessaging.SendExpress.OAuthTokenFetchResult",
+      !oauth_token.empty());
   if (oauth_token.empty()) {
+    NS_LOG(ERROR) << __func__ << ": Failed to fetch OAuth token.";
     std::move(callback).Run(false);
     return;
   }