Instrument SerialExtensionHostQueue::ProcessOneHost Codepaths to Find Jank

BUG=464206

Review URL: https://codereview.chromium.org/978163002

Cr-Commit-Position: refs/heads/master@{#319332}
diff --git a/extensions/browser/extension_host.cc b/extensions/browser/extension_host.cc
index 61d0626d..a47d654 100644
--- a/extensions/browser/extension_host.cc
+++ b/extensions/browser/extension_host.cc
@@ -7,6 +7,7 @@
 #include "base/logging.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram_macros.h"
+#include "base/profiler/scoped_tracker.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/public/browser/browser_context.h"
@@ -133,8 +134,16 @@
 }
 
 void ExtensionHost::CreateRenderViewNow() {
+  // TODO(robliao): Remove ScopedTracker below once crbug.com/464206 is fixed.
+  tracked_objects::ScopedTracker tracking_profile1(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "464206 ExtensionHost::CreateRenderViewNow1"));
   LoadInitialURL();
   if (IsBackgroundPage()) {
+    // TODO(robliao): Remove ScopedTracker below once crbug.com/464206 is fixed.
+    tracked_objects::ScopedTracker tracking_profile2(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "464206 ExtensionHost::CreateRenderViewNow2"));
     DCHECK(IsRenderViewLive());
     if (extension_) {
       std::string group_name = base::FieldTrialList::FindFullName(
@@ -146,6 +155,10 @@
         host_contents_->WasHidden();
       }
     }
+    // TODO(robliao): Remove ScopedTracker below once crbug.com/464206 is fixed.
+    tracked_objects::ScopedTracker tracking_profile3(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "464206 ExtensionHost::CreateRenderViewNow3"));
     // Connect orphaned dev-tools instances.
     delegate_->OnRenderViewCreatedForBackgroundPage(this);
   }