glic: Fix performance metrics for short responses.

In a short response the web client will call OnResponseStopped() without
first calling OnResponseStarted(). This CL handles this by synthetically
invoking OnResponseStarted() in this case.

Change-Id: Ia96dc0d682ff4d4f9d213c9ecbca557023af81e0
Bug: 391417447, 399151164
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6300792
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Erik Chen <erikchen@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1424796}

chrome/browser/glic/glic_metrics.cc

@@ -159,6 +159,7 @@ void GlicMetrics::OnUserInputSubmitted(mojom::WebClientMode mode) {
 }
 
 void GlicMetrics::OnResponseStarted() {
+  response_started_ = true;
   base::RecordAction(base::UserMetricsAction("GlicResponseStart"));
 
   // It doesn't make sense to record response start without input submission.
@@ -219,6 +220,12 @@ void GlicMetrics::OnResponseStarted() {
 }
 
 void GlicMetrics::OnResponseStopped() {
+  // The client may call "stopped" without "started" for very short responses.
+  // We synthetically call it ourselves in this case.
+  if (!input_submitted_time_.is_null() && !response_started_) {
+    OnResponseStarted();
+  }
+
   base::RecordAction(base::UserMetricsAction("GlicResponseStop"));
 
   if (input_submitted_time_.is_null()) {
@@ -234,6 +241,7 @@ void GlicMetrics::OnResponseStopped() {
   input_submitted_time_ = base::TimeTicks();
   did_request_context_ = false;
   source_id_ = no_url_source_id_;
+  response_started_ = false;
 }
 
 void GlicMetrics::OnSessionTerminated() {

chrome/browser/glic/glic_metrics.h

@@ -102,6 +102,10 @@ class GlicMetrics {
   // value.
   bool is_enabled_ = false;
 
+  // Set to true in OnResponseStarted() and set to false in OnResponseStopped().
+  // This is a workaround and should be removed, see crbug.com/399151164.
+  bool response_started_ = false;
+
   // Holds subscriptions for callbacks.
   std::vector<base::CallbackListSubscription> subscriptions_;