predictors: Collect page load metrics for ResourcePrefetchPredictor.

chrome/browser/page_load_metrics/page_load_metrics_initialize.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/page_load_metrics_initialize.h"
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "chrome/browser/page_load_metrics/metrics_web_contents_observer.h"
 #if defined(OS_ANDROID)
 #include "chrome/browser/page_load_metrics/observers/android_page_load_metrics_observer.h"
 #endif  // OS_ANDROID
 #include "chrome/browser/page_load_metrics/observers/aborts_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/amp_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/core_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/css_scanning_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/from_gws_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/google_captcha_observer.h"
 #include "chrome/browser/page_load_metrics/observers/https_engagement_metrics/https_engagement_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/no_state_prefetch_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/prerender_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/previews_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/protocol_page_load_metrics_observer.h"
+#include "chrome/browser/page_load_metrics/observers/resource_prefetch_predictor_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/service_worker_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_embedder_interface.h"
 #include "chrome/browser/page_load_metrics/page_load_tracker.h"
 #include "chrome/browser/prerender/prerender_contents.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search/search.h"
 #include "components/rappor/rappor_service_impl.h"
 #include "content/public/browser/web_contents.h"
 #include "url/gurl.h"
 
@@ skipping 51 matching lines @@
     std::unique_ptr<page_load_metrics::PageLoadMetricsObserver>
         no_state_prefetch_observer =
             NoStatePrefetchPageLoadMetricsObserver::CreateIfNeeded(
                 web_contents_);
     if (no_state_prefetch_observer)
       tracker->AddObserver(std::move(no_state_prefetch_observer));
 #if defined(OS_ANDROID)
     tracker->AddObserver(
         base::MakeUnique<AndroidPageLoadMetricsObserver>(web_contents_));
 #endif  // OS_ANDROID
+    std::unique_ptr<page_load_metrics::PageLoadMetricsObserver>
+        resource_prefetch_predictor_observer =

[Benoit L, 2017/01/13 17:31:56]

nit: observer is fine as a variable name here :-)

[alexilin, 2017/01/24 12:49:20]

I'm trying to be more consistent with the names around
(no_state_prefetch_observer, prerender_observer). 
This name isn't scoped so it will be confusing to use it along with other
observers.

+            ResourcePrefetchPredictorPageLoadMetricsObserver::CreateIfNeeded(
+                web_contents_);
+    if (resource_prefetch_predictor_observer)
+      tracker->AddObserver(std::move(resource_prefetch_predictor_observer));
   } else {
     std::unique_ptr<page_load_metrics::PageLoadMetricsObserver>
         prerender_observer =
             PrerenderPageLoadMetricsObserver::CreateIfNeeded(web_contents_);
     if (prerender_observer)
       tracker->AddObserver(std::move(prerender_observer));
   }
 }
 
 bool PageLoadMetricsEmbedder::IsPrerendering() const {
@@ skipping 11 matching lines @@
 
 }  // namespace
 
 void InitializePageLoadMetricsForWebContents(
     content::WebContents* web_contents) {
   page_load_metrics::MetricsWebContentsObserver::CreateForWebContents(
       web_contents, base::MakeUnique<PageLoadMetricsEmbedder>(web_contents));
 }
 
 }  // namespace chrome