[PageLoadMetrics] Handle case where navigation aborts

chrome/browser/page_load_metrics/observers/ads_page_load_metrics_observer.cc

 // Copyright 2017 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/observers/ads_page_load_metrics_observer.h"
 
 #include <string>
 #include <utility>
 
 #include "base/feature_list.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/string_util.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_util.h"
 #include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/web_contents.h"
 #include "url/gurl.h"
 
 namespace {
 
 const base::Feature kAdsFeature{"AdsMetrics",
                                 base::FEATURE_DISABLED_BY_DEFAULT};
 
 bool FrameIsAd(content::NavigationHandle* navigation_handle) {
-  content::RenderFrameHost* current_frame_host =
-      navigation_handle->GetRenderFrameHost();
-  DCHECK(current_frame_host);
-  const std::string& name = current_frame_host->GetFrameName();
-  const GURL& url = navigation_handle->GetURL();
-
   // Because sub-resource filtering isn't always enabled, and doesn't work
   // well in monitoring mode (no CSS enforcement), it's difficult to identify
   // ads. Google ads are prevalent and easy to track, so we'll start by
   // tracking those. Note that the frame name can be very large, so be careful
   // to avoid full string searches if possible.
   // TODO(jkarlin): Track other ad networks that are easy to identify.
-  return base::StartsWith(name, "google_ads_iframe",
-                          base::CompareCase::SENSITIVE) ||
-         base::StartsWith(name, "google_ads_frame",
-                          base::CompareCase::SENSITIVE) ||
-         (url.host_piece() == "tpc.googlesyndication.com" &&
-          base::StartsWith(url.path_piece(), "/safeframe",
-                           base::CompareCase::SENSITIVE));
+
+  // In case the navigation aborted, look up the RFH by the Frame Tree Node
+  // ID. It returns the committed frame host or the initial frame host for the
+  // frame if no committed host exists. Using a previous host is fine because
+  // once a frame has an ad we always consider it to have an ad.
+  // We use the unsafe method of FindFrameByFrameTreeNodeId because we're not
+  // concerned with which process the frame lives on (we're just measuring
+  // bytes and not granting security priveleges).
+  content::RenderFrameHost* current_frame_host =
+      navigation_handle->GetWebContents()->UnsafeFindFrameByFrameTreeNodeId(
+          navigation_handle->GetFrameTreeNodeId());
+  if (current_frame_host) {
+    const std::string& frame_name = current_frame_host->GetFrameName();
+    if (base::StartsWith(frame_name, "google_ads_iframe",
+                         base::CompareCase::SENSITIVE) ||
+        base::StartsWith(frame_name, "google_ads_frame",
+                         base::CompareCase::SENSITIVE)) {
+      return true;
+    }
+  }
+
+  const GURL& url = navigation_handle->GetURL();
+  return url.host_piece() == "tpc.googlesyndication.com" &&
+         base::StartsWith(url.path_piece(), "/safeframe",
+                          base::CompareCase::SENSITIVE);
 }
 
 }  // namespace
 
 AdsPageLoadMetricsObserver::AdFrameData::AdFrameData(
     FrameTreeNodeId frame_tree_node_id)
     : frame_bytes(0u),
       frame_bytes_uncached(0u),
       frame_tree_node_id(frame_tree_node_id) {}
 
@@ skipping 15 matching lines @@
 
   // The main frame is never considered an ad.
   ad_frames_data_[navigation_handle->GetFrameTreeNodeId()] = nullptr;
   ProcessOngoingNavigationResource(navigation_handle->GetFrameTreeNodeId());
   return CONTINUE_OBSERVING;
 }
 
 page_load_metrics::PageLoadMetricsObserver::ObservePolicy
 AdsPageLoadMetricsObserver::OnDidFinishSubFrameNavigation(
     content::NavigationHandle* navigation_handle) {
+  // Determine if the frame is part of an existing ad, the root of a new ad,
+  // or a non-ad frame. Once a frame is labled as an ad, it is always
+  // considered an ad, even if it navigates to a non-ad page. This function
+  // labels all of a page's frames, even those that fail to commit.
   FrameTreeNodeId frame_tree_node_id = navigation_handle->GetFrameTreeNodeId();
-
-  if (!navigation_handle->HasCommitted() ||
-      navigation_handle->IsSameDocument() || navigation_handle->IsErrorPage()) {
-    // We're not interested in tracking this navigation. In case we've seen a
-    // resource for the navigation before this message, clear it from
-    // ongoing_navigation_resources_.
-    ongoing_navigation_resources_.erase(frame_tree_node_id);
-    return CONTINUE_OBSERVING;
-  }
-
   content::RenderFrameHost* parent_frame_host =
-      navigation_handle->GetRenderFrameHost()->GetParent();
-  DCHECK(parent_frame_host);
-
-  bool top_level_subframe = !parent_frame_host->GetParent();
+      navigation_handle->GetParentFrame();
 
   const auto& id_and_data = ad_frames_data_.find(frame_tree_node_id);
   if (id_and_data != ad_frames_data_.end()) {
     // An existing subframe is navigating again.
     if (id_and_data->second) {
       // The subframe was an ad to begin with, keep tracking it as an ad.
       ProcessOngoingNavigationResource(frame_tree_node_id);
 
       if (frame_tree_node_id == id_and_data->second->frame_tree_node_id) {
         // This is the top-most frame in the ad.
         UMA_HISTOGRAM_BOOLEAN(
             "PageLoad.Clients.Ads.Google.Navigations.AdFrameRenavigatedToAd",
             FrameIsAd(navigation_handle));
       }
-
       return CONTINUE_OBSERVING;
     }
     // This frame was previously not an ad, process it as usual. If it had
     // any child frames that were ads, those will still be recorded.
     UMA_HISTOGRAM_BOOLEAN(
         "PageLoad.Clients.Ads.Google.Navigations.NonAdFrameRenavigatedToAd",
         FrameIsAd(navigation_handle));
-  } else if (top_level_subframe) {
+  } else if (navigation_handle->IsParentMainFrame()) {
     top_level_subframe_count_ += 1;
   }
 
   // Determine who the parent frame's ad ancestor is.
   const auto& parent_id_and_data =
       ad_frames_data_.find(parent_frame_host->GetFrameTreeNodeId());
   DCHECK(parent_id_and_data != ad_frames_data_.end());
   AdFrameData* ad_data = parent_id_and_data->second;
 
   if (!ad_data && FrameIsAd(navigation_handle)) {
     // This frame is not nested within an ad frame but is itself an ad.
     ad_frames_data_storage_.emplace_back(frame_tree_node_id);
     ad_data = &ad_frames_data_storage_.back();
   }
 
   ad_frames_data_[frame_tree_node_id] = ad_data;
 
-  if (top_level_subframe && ad_data)
+  if (navigation_handle->IsParentMainFrame() && ad_data)
     top_level_ad_frame_count_ += 1;
 
   ProcessOngoingNavigationResource(frame_tree_node_id);
   return CONTINUE_OBSERVING;
 }
 
 page_load_metrics::PageLoadMetricsObserver::ObservePolicy
 AdsPageLoadMetricsObserver::FlushMetricsOnAppEnterBackground(
     const page_load_metrics::PageLoadTiming& timing,
     const page_load_metrics::PageLoadExtraInfo& extra_info) {
@@ skipping 22 matching lines @@
     // Data uris should be accounted for in the generating resource, not
     // here. Blobs for PlzNavigate shouldn't be counted as the http resource
     // was already counted. Blobs for other things like CacheStorage or
     // IndexedDB are also ignored for now, as they're not normal HTTP loads.
     return;
   }
 
   const auto& id_and_data =
       ad_frames_data_.find(extra_request_info.frame_tree_node_id);
   if (id_and_data == ad_frames_data_.end()) {
-    // This resouce is for a frame that hasn't yet committed. It must be the
-    // main document for the frame. Hold onto it and once it commits we'll run
-    // it in ProcessOngoingNavigationResource.
-    // TODO(jkarlin): Plumb the resource type through and DCHECK that the type
-    // is document.
-    auto it_and_success = ongoing_navigation_resources_.emplace(
+    // This resource is for a frame that hasn't ever finished a navigation. We
+    // expect it to be the frame's main resource but don't have enough
+    // confidence in that to dcheck it. For example, there might be races
+    // between doc.written resources and navigation failure.
+    // TODO(jkarlin): Add UMA to measure how often we see multiple resources
+    // for a frame before navigation finishes.
+    ongoing_navigation_resources_.emplace(
         std::piecewise_construct,
         std::forward_as_tuple(extra_request_info.frame_tree_node_id),
         std::forward_as_tuple(
             extra_request_info.url, extra_request_info.frame_tree_node_id,
             extra_request_info.was_cached, extra_request_info.raw_body_bytes,
             extra_request_info.original_network_content_length, nullptr,
             extra_request_info.resource_type));
-    DCHECK(it_and_success.second);
     return;
   }
 
   page_bytes_ += extra_request_info.raw_body_bytes;
   if (!extra_request_info.was_cached)
     uncached_page_bytes_ += extra_request_info.raw_body_bytes;
 
   // Determine if the frame (or its ancestor) is an ad, if so attribute the
   // bytes to the highest ad ancestor.
   AdFrameData* ancestor_data = id_and_data->second;
@@ skipping 86 matching lines @@
 void AdsPageLoadMetricsObserver::ProcessOngoingNavigationResource(
     FrameTreeNodeId frame_tree_node_id) {
   const auto& frame_id_and_request =
       ongoing_navigation_resources_.find(frame_tree_node_id);
   if (frame_id_and_request == ongoing_navigation_resources_.end())
     return;
 
   ProcessLoadedResource(frame_id_and_request->second);
   ongoing_navigation_resources_.erase(frame_id_and_request);
 }