Send an event to the page load metrics to track resource starting.

chrome/browser/page_load_metrics/metrics_web_contents_observer.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/page_load_metrics/metrics_web_contents_observer.h"
 
 #include <algorithm>
 #include <ostream>
 #include <string>
 #include <utility>
@@ skipping 234 matching lines @@
     // investigation is needed to confirm that all cases would be handled
     // correctly (for example Link: preloads).
     if (committed_load_ &&
         creation_time >= committed_load_->navigation_start()) {
       return committed_load_.get();
     }
   }
   return nullptr;
 }
 
+void MetricsWebContentsObserver::OnRequestStarted(
+    const content::GlobalRequestID& request_id,
+    content::ResourceType resource_type,
+    base::TimeTicks creation_time) {
+  // Note for the main HTML page, the tracker may not exist yet, so
+  // OnStartedResource will not be called for the main page.  While the main
+  // page is not being tracked today, if we do decide to track it, we will need
+  // to first make sure that GlobalRequestID is set in an earlier callback.
+  // TODO(bmcquade): Evaluate whether moving tracker creation to
+  // DidStartNavigation would address this.
+  PageLoadTracker* tracker =
+      GetTrackerOrNullForRequest(request_id, resource_type, creation_time);
+  if (tracker) {
+    ExtraRequestStartInfo extra_request_start_info(resource_type);
+    tracker->OnStartedResource(extra_request_start_info);
+  }
+}
+
 void MetricsWebContentsObserver::OnRequestComplete(
     const content::GlobalRequestID& request_id,
     content::ResourceType resource_type,
     bool was_cached,
     std::unique_ptr<data_reduction_proxy::DataReductionProxyData>
         data_reduction_proxy_data,
     int64_t raw_body_bytes,
     int64_t original_content_length,
     base::TimeTicks creation_time) {
   PageLoadTracker* tracker =
       GetTrackerOrNullForRequest(request_id, resource_type, creation_time);
   if (tracker) {
-    ExtraRequestInfo extra_request_info(
+    ExtraRequestCompleteInfo extra_request_complete_info(
         was_cached, raw_body_bytes, was_cached ? 0 : original_content_length,
-        std::move(data_reduction_proxy_data));
-    tracker->OnLoadedResource(extra_request_info);
+        std::move(data_reduction_proxy_data), resource_type);
+    tracker->OnLoadedResource(extra_request_complete_info);
   }
 }
 
 void MetricsWebContentsObserver::OnNavigationDelayComplete(
     content::NavigationHandle* navigation_handle,
     base::TimeDelta scheduled_delay,
     base::TimeDelta actual_delay) {
   auto it = provisional_loads_.find(navigation_handle);
   if (it == provisional_loads_.end())
     return;
@@ skipping 304 matching lines @@
     content::NavigationHandle* navigation_handle) const {
   DCHECK(navigation_handle->IsInMainFrame());
   DCHECK(!navigation_handle->HasCommitted() ||
          !navigation_handle->IsSameDocument());
 
   return BrowserPageTrackDecider(embedder_interface_.get(), web_contents(),
                                  navigation_handle).ShouldTrack();
 }
 
 }  // namespace page_load_metrics