Add perf histogram and tests for inline signin

chrome/browser/ui/webui/signin/inline_login_handler.cc

Index: chrome/browser/ui/webui/signin/inline_login_handler.cc
diff --git a/chrome/browser/ui/webui/signin/inline_login_handler.cc b/chrome/browser/ui/webui/signin/inline_login_handler.cc
index 6c6e9110734ab67b83de49c47ce2690d505587c6..3b84a84d211f7b67799a96b6a4bea460946da5c6 100644
--- a/chrome/browser/ui/webui/signin/inline_login_handler.cc
+++ b/chrome/browser/ui/webui/signin/inline_login_handler.cc
@@ -5,12 +5,16 @@
 #include "chrome/browser/ui/webui/signin/inline_login_handler.h"
 
 #include "base/bind.h"
+#include "base/metrics/histogram.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/signin/signin_promo.h"
+#include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_ui.h"
 #include "google_apis/gaia/gaia_urls.h"
 
-InlineLoginHandler::InlineLoginHandler() {}
+InlineLoginHandler::InlineLoginHandler()
+    : load_start_time_(base::Time::Now()) {}
 
 InlineLoginHandler::~InlineLoginHandler() {}
 
@@ -18,6 +22,9 @@ void InlineLoginHandler::RegisterMessages() {
   web_ui()->RegisterMessageCallback("initialize",
       base::Bind(&InlineLoginHandler::HandleInitializeMessage,
                   base::Unretained(this)));
+  web_ui()->RegisterMessageCallback("loginUIInitialized",
+      base::Bind(&InlineLoginHandler::HandleLoginUIInitializedMessage,
+                  base::Unretained(this)));
   web_ui()->RegisterMessageCallback("completeLogin",
       base::Bind(&InlineLoginHandler::HandleCompleteLoginMessage,
                   base::Unretained(this)));
@@ -37,6 +44,31 @@ void InlineLoginHandler::HandleInitializeMessage(const base::ListValue* args) {
   web_ui()->CallJavascriptFunction("inline.login.loadAuthExtension", params);
 }
 
+void InlineLoginHandler::HandleLoginUIInitializedMessage(
+    const base::ListValue* args) {
+  if (load_start_time_.is_max())
+    return;
+
+  double gaia_start_time_str;
+  double gaia_stop_time_str;
+  CHECK(args->GetDouble(0, &gaia_start_time_str));
+  CHECK(args->GetDouble(1, &gaia_stop_time_str));
+
+  const GURL& current_url = web_ui()->GetWebContents()->GetURL();
+  signin::Source source = signin::GetSourceForPromoURL(current_url);
+  const std::string& prefix = source == signin::SOURCE_START_PAGE ?
+      "Signin.InlineUI.LoadOnStartup." :
+      "Signin.InlineUI.LoadAfterStartup.";
+
+  const base::Time gaia_start_time(base::Time::FromJsTime(gaia_start_time_str));
+  UMA_HISTOGRAM_MEDIUM_TIMES(
+      prefix + "PreGaiaLoadTime", gaia_start_time - load_start_time_);
+  UMA_HISTOGRAM_MEDIUM_TIMES(
+      prefix + "GaiaLoadTime",
+      base::Time::FromJsTime(gaia_stop_time_str) - gaia_start_time);
+  load_start_time_ = base::Time::Max();
+}
+
 void InlineLoginHandler::HandleCompleteLoginMessage(
     const base::ListValue* args) {
   CompleteLogin(args);