Replace the ExtensionHost load UMAs (Extensions.BackgroundPageLoadTime and friends)

extensions/browser/extension_host.cc

Index: extensions/browser/extension_host.cc
diff --git a/extensions/browser/extension_host.cc b/extensions/browser/extension_host.cc
index 7874528d272ba54f76d1f4c78d462533d2b78fc4..f82480c27b9a15331228ef918c81ababb19f6a80 100644
--- a/extensions/browser/extension_host.cc
+++ b/extensions/browser/extension_host.cc
@@ -12,7 +12,7 @@
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/field_trial.h"
-#include "base/metrics/histogram.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/public/browser/browser_context.h"
@@ -152,9 +152,10 @@ ExtensionHost::ExtensionHost(const Extension* extension,
 
 ExtensionHost::~ExtensionHost() {
   if (extension_host_type_ == VIEW_TYPE_EXTENSION_BACKGROUND_PAGE &&
-      extension_ && BackgroundInfo::HasLazyBackgroundPage(extension_)) {
+      extension_ && BackgroundInfo::HasLazyBackgroundPage(extension_) &&
+      since_created_.get()) {
     UMA_HISTOGRAM_LONG_TIMES("Extensions.EventPageActiveTime",
-                             since_created_.Elapsed());
+                             since_created_->Elapsed());
   }
   content::NotificationService::current()->Notify(
       extensions::NOTIFICATION_EXTENSION_HOST_DESTROYED,
@@ -238,6 +239,7 @@ const GURL& ExtensionHost::GetURL() const {
 }
 
 void ExtensionHost::LoadInitialURL() {
+  since_created_.reset(new base::ElapsedTimer());
   host_contents_->GetController().LoadURL(
       initial_url_, content::Referrer(), ui::PAGE_TRANSITION_LINK,
       std::string());
@@ -306,23 +308,24 @@ void ExtensionHost::DidStopLoading(content::RenderViewHost* render_view_host) {
   did_stop_loading_ = true;
   OnDidStopLoading();
   if (notify) {
+    CHECK(since_created_.get());
     if (extension_host_type_ == VIEW_TYPE_EXTENSION_BACKGROUND_PAGE) {
       if (extension_ && BackgroundInfo::HasLazyBackgroundPage(extension_)) {
-        UMA_HISTOGRAM_TIMES("Extensions.EventPageLoadTime",
-                            since_created_.Elapsed());
+        UMA_HISTOGRAM_MEDIUM_TIMES("Extensions.EventPageLoadTime",

[Yoyo Zhou, 2015/02/06 01:59:12]

I think this is the right change, even though on my machine I don't have any
that go over about 5 seconds.

+                                   since_created_->Elapsed());
       } else {
-        UMA_HISTOGRAM_TIMES("Extensions.BackgroundPageLoadTime",
-                            since_created_.Elapsed());
+        UMA_HISTOGRAM_MEDIUM_TIMES("Extensions.BackgroundPageLoadTime",
+                                   since_created_->Elapsed());

[Ilya Sherman, 2015/02/06 02:56:13]

If you change what macro is used -- really, if you change the underlying set of
buckets for the histogram -- then you do indeed need to rename the histogram as
well.

       }
     } else if (extension_host_type_ == VIEW_TYPE_EXTENSION_DIALOG) {
       UMA_HISTOGRAM_TIMES("Extensions.DialogLoadTime",
-                          since_created_.Elapsed());
+                          since_created_->Elapsed());
     } else if (extension_host_type_ == VIEW_TYPE_EXTENSION_POPUP) {
       UMA_HISTOGRAM_TIMES("Extensions.PopupLoadTime",
-                          since_created_.Elapsed());
+                          since_created_->Elapsed());
     } else if (extension_host_type_ == VIEW_TYPE_EXTENSION_INFOBAR) {
       UMA_HISTOGRAM_TIMES("Extensions.InfobarLoadTime",
-        since_created_.Elapsed());
+                          since_created_->Elapsed());
     }
 
     // Send the notification last, because it might result in this being