[PageLoadMetrics] Relax invariants and log the exceptions

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 197 matching lines @@
   auto it = provisional_loads_.find(navigation_handle);
   if (it == provisional_loads_.end())
     return;
   it->second->WillProcessNavigationResponse(navigation_handle);
 }
 
 PageLoadTracker* MetricsWebContentsObserver::GetTrackerOrNullForRequest(
     const content::GlobalRequestID& request_id,
     content::ResourceType resource_type,
     base::TimeTicks creation_time) {
-  if (resource_type == content::RESOURCE_TYPE_MAIN_FRAME) {
+  // TODO(jkarlin): The WebContentsTester framework doesn't provide a default
+  // GlobalRequestID to its NavigationHandles. Once the test framework
+  // supports real ids, remove the request_id != content::GlobalRequestID()
+  // condition. See https://crbug.com/711352.
+  if (resource_type == content::RESOURCE_TYPE_MAIN_FRAME &&
+      request_id != content::GlobalRequestID()) {
     // The main frame request can complete either before or after commit, so we
     // look at both provisional loads and the committed load to find a
     // PageLoadTracker with a matching request id. See https://goo.gl/6TzCYN for
     // more details.
     for (const auto& kv : provisional_loads_) {
       PageLoadTracker* candidate = kv.second.get();
       if (candidate->HasMatchingNavigationRequestID(request_id)) {
         return candidate;
       }
     }
@@ skipping 413 matching lines @@
     observer_->RemoveTestingObserver(this);
     observer_ = nullptr;
   }
 }
 
 void MetricsWebContentsObserver::TestingObserver::OnGoingAway() {
   observer_ = nullptr;
 }
 
 }  // namespace page_load_metrics