Fix for URL opening code

chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc

Index: chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc
diff --git a/chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc b/chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc
index 9055c02b178646427d2b597fe65e7c321dbb6ea2..cd92263a1adec6321607a26a242c4b990cec2347 100644
--- a/chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc
+++ b/chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc
@@ -21,6 +21,9 @@
 #include "chrome/browser/chrome_browser_main.h"
 #include "chrome/browser/mac/bluetooth_utility.h"
 #include "chrome/browser/shell_integration.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_list.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "components/flags_ui/pref_service_flags_storage.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/common/content_switches.h"
@@ -420,11 +423,34 @@ void ChromeBrowserMainExtraPartsMetrics::PostBrowserStart() {
   is_screen_observer_ = true;
 
 #if !defined(OS_ANDROID)
-  metrics::BeginFirstWebContentsProfiling();
+  const BrowserList* browser_list = BrowserList::GetInstance();
+
+  auto first_browser = browser_list->begin();
+  if (first_browser == browser_list->end())
+    DCHECK(0);

[sky, 2017/04/07 21:52:14]

I'm not entirely sure it's valid to assume there is at least one browser. In
particular starting up in background mode (or other similar things) may result
in no browsers.

[eugenebng, 2017/04/10 12:04:43]

Thank you for comments, overlooked this part of code. Have to fix this if the
code will not be completely changed/rewritten in the first place.

+
+  TabStripModel* tab_strip = (*first_browser)->tab_strip_model();
+  DCHECK(tab_strip);
+  if (tab_strip->empty()) {
+    // Start web contents profiling later, when there will be a tab to profile
+    tab_strip->AddObserver(this);

[sky, 2017/04/07 21:52:14]

Make sure you deal with case of this being deleted before TabInsertAt.

+  } else {
+    metrics::BeginFirstWebContentsProfiling();
+  }
   metrics::TabUsageRecorder::InitializeIfNeeded();
 #endif  // !defined(OS_ANDROID)
 }
 
+void ChromeBrowserMainExtraPartsMetrics::TabInsertedAt(
+    TabStripModel* tab_strip_model,
+    content::WebContents* contents,
+    int index,
+    bool foreground) {
+  VLOG(0) << "begin profiling!";

[sky, 2017/04/07 21:52:14]

Remove VLOGs.

+  metrics::BeginFirstWebContentsProfiling();
+  tab_strip_model->RemoveObserver(this);
+}
+
 void ChromeBrowserMainExtraPartsMetrics::OnDisplayAdded(
     const display::Display& new_display) {
   EmitDisplaysChangedMetric();