[PageLoadMetrics] Relax invariants and log the exceptions

chrome/browser/page_load_metrics/metrics_web_contents_observer.cc

Index: chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
diff --git a/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc b/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
index 711eed8760f7c30adc9699d412f778bc571a9d3c..0f8527c5d6c0ff39b8f656a90e6f1ed91377e443 100644
--- a/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
+++ b/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
@@ -215,7 +215,12 @@ 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 test frameworks don't provide a default
+  // GlobalRequestID to their NavigationHandles. Once the test frameworks
+  // support real ids, remove the request_id != content::GlobalRequestID()
+  // condition. See https://crbug.com/711352.

[Bryan McQuade, 2017/05/16 16:22:36]

Does csharrison's https://codereview.chromium.org/2885453003 address this?

[jkarlin, 2017/05/16 17:16:08]

It addresses it for tests that use Navigation Simulator, but not tests that use
WebContentsTester which is the majority. I've updated the comment.

+  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