8 files changed, 35 insertions, 12 deletions
diff --git a/chrome/app/chrome_exe_main_win.cc b/chrome/app/chrome_exe_main_win.cc
index abba672..bffca3b 100644
--- a/chrome/app/chrome_exe_main_win.cc
+++ b/chrome/app/chrome_exe_main_win.cc
@@ -83,8 +83,10 @@ bool AttemptFastNotify(const CommandLine& command_line) {
   policy::path_parser::CheckUserDataDirPolicy(&user_data_dir);
 
   HWND chrome = chrome::FindRunningChromeWindow(user_data_dir);
-  return chrome &&
-      chrome::AttemptToNotifyRunningChrome(chrome) == chrome::NOTIFY_SUCCESS;
+  if (!chrome)
+    return false;
+  return chrome::AttemptToNotifyRunningChrome(chrome, true) ==
+      chrome::NOTIFY_SUCCESS;
 }
 
 }  // namespace
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index 8de46fd..a959216 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -427,9 +427,15 @@ bool ProcessSingletonNotificationCallback(
         command_line.GetSwitchValueASCII(switches::kOriginalProcessStartTime);
     int64 remote_start_time;
     if (base::StringToInt64(start_time_string, &remote_start_time)) {
-      UMA_HISTOGRAM_LONG_TIMES(
-          "Startup.WarmStartTimeFromRemoteProcessStart",
-          base::Time::Now() - base::Time::FromInternalValue(remote_start_time));
+      base::TimeDelta elapsed =
+          base::Time::Now() - base::Time::FromInternalValue(remote_start_time);
+      if (command_line.HasSwitch(switches::kFastStart)) {
+        UMA_HISTOGRAM_LONG_TIMES(
+            "Startup.WarmStartTimeFromRemoteProcessStartFast", elapsed);
+      } else {
+        UMA_HISTOGRAM_LONG_TIMES(
+            "Startup.WarmStartTimeFromRemoteProcessStart", elapsed);
+      }
     }
   }
 
diff --git a/chrome/browser/chrome_process_finder_win.cc b/chrome/browser/chrome_process_finder_win.cc
index c7a4985..34f6761 100644
--- a/chrome/browser/chrome_process_finder_win.cc
+++ b/chrome/browser/chrome_process_finder_win.cc
@@ -93,7 +93,7 @@ std::string EscapeQueryParamValue(const std::string& text, bool use_plus) {
 
 // END COPY from net/base/escape.cc
 
-}
+}  // namespace
 
 namespace chrome {
 
@@ -102,7 +102,8 @@ HWND FindRunningChromeWindow(const base::FilePath& user_data_dir) {
                       user_data_dir.value().c_str());
 }
 
-NotifyChromeResult AttemptToNotifyRunningChrome(HWND remote_window) {
+NotifyChromeResult AttemptToNotifyRunningChrome(HWND remote_window,
+                                                bool fast_start) {
   DCHECK(remote_window);
   static const char kSearchUrl[] =
       "http://www.google.com/search?q=%s&sourceid=chrome&ie=UTF-8";
@@ -150,6 +151,9 @@ NotifyChromeResult AttemptToNotifyRunningChrome(HWND remote_window) {
       base::Int64ToString(
           base::CurrentProcessInfo::CreationTime()->ToInternalValue()));
 
+  if (fast_start)
+    command_line.AppendSwitch(switches::kFastStart);
+
   // Send the command line to the remote chrome window.
   // Format is "START\0<<<current directory>>>\0<<<commandline>>>".
   std::wstring to_send(L"START\0", 6);  // want the NULL in the string.
diff --git a/chrome/browser/chrome_process_finder_win.h b/chrome/browser/chrome_process_finder_win.h
index 46c49ed..bc5c81f 100644
--- a/chrome/browser/chrome_process_finder_win.h
+++ b/chrome/browser/chrome_process_finder_win.h
@@ -25,7 +25,9 @@ HWND FindRunningChromeWindow(const base::FilePath& user_data_dir);
 // Attempts to send the current command line to an already running instance of
 // Chrome via a WM_COPYDATA message.
 // Returns true if a running Chrome is found and successfully notified.
-NotifyChromeResult AttemptToNotifyRunningChrome(HWND remote_window);
+// |fast_start| is true when this is being called on the window fast start path.
+NotifyChromeResult AttemptToNotifyRunningChrome(HWND remote_window,
+                                                bool fast_start);
 
 }  // namespace chrome
 
diff --git a/chrome/browser/process_singleton_win.cc b/chrome/browser/process_singleton_win.cc
index cb4a1c3..237004a 100644
--- a/chrome/browser/process_singleton_win.cc
+++ b/chrome/browser/process_singleton_win.cc
@@ -288,7 +288,7 @@ ProcessSingleton::NotifyResult ProcessSingleton::NotifyOtherProcess() {
     return PROCESS_NONE;
   }
 
-  switch (chrome::AttemptToNotifyRunningChrome(remote_window_)) {
+  switch (chrome::AttemptToNotifyRunningChrome(remote_window_, false)) {
     case chrome::NOTIFY_SUCCESS:
       return PROCESS_NOTIFIED;
     case chrome::NOTIFY_FAILED:
diff --git a/chrome/browser/ui/app_list/app_list_service.cc b/chrome/browser/ui/app_list/app_list_service.cc
index 717e94c..8ae72eb 100644
--- a/chrome/browser/ui/app_list/app_list_service.cc
+++ b/chrome/browser/ui/app_list/app_list_service.cc
@@ -24,7 +24,7 @@ base::TimeDelta GetTimeFromOriginalProcessStart(
   return base::Time::Now() - base::Time::FromInternalValue(remote_start_time);
 }
 
-}
+}  // namespace
 
 // static
 void AppListService::RegisterPrefs(PrefRegistrySimple* registry) {
@@ -41,8 +41,11 @@ void AppListService::RecordShowTimings(const CommandLine& command_line) {
   // The presence of kOriginalProcessStartTime implies that another process
   // has sent us its command line to handle, ie: we are already running.
   if (command_line.HasSwitch(switches::kOriginalProcessStartTime)) {
-     UMA_HISTOGRAM_LONG_TIMES("Startup.ShowAppListWarmStart",
-                              GetTimeFromOriginalProcessStart(command_line));
+    base::TimeDelta elapsed = GetTimeFromOriginalProcessStart(command_line);
+    if (command_line.HasSwitch(switches::kFastStart))
+      UMA_HISTOGRAM_LONG_TIMES("Startup.ShowAppListWarmStartFast", elapsed);
+    else
+      UMA_HISTOGRAM_LONG_TIMES("Startup.ShowAppListWarmStart", elapsed);
   } else {
     // base::CurrentProcessInfo::CreationTime() is only defined on win/mac.
 #if defined(OS_WIN) || defined(OS_MACOSX)
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 57c7c57..3d0e582 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -750,6 +750,11 @@ const char kExtraSearchQueryParams[]        = "extra-search-query-params";
 // is UNKNOWN.
 const char kFakeVariationsChannel[]         = "fake-variations-channel";
 
+// If this flag is present then this command line is being delegated to an
+// already running chrome process via the fast path, ie: before chrome.dll is
+// loaded. It is useful to tell the difference for tracking purposes.
+const char kFastStart[]            = "fast-start";
+
 // These two flags are added around the switches about:flags adds to the
 // command line. This is useful to see which switches were added by about:flags
 // on about:version. They don't have any effect.
diff --git a/chrome/common/chrome_switches.h b/chrome/common/chrome_switches.h
index 4c2aa46..b142607 100644
--- a/chrome/common/chrome_switches.h
+++ b/chrome/common/chrome_switches.h
@@ -210,6 +210,7 @@ extern const char kExtensionProcess[];
 extern const char kExtensionsUpdateFrequency[];
 extern const char kExtraSearchQueryParams[];
 extern const char kFakeVariationsChannel[];
+extern const char kFastStart[];
 extern const char kFlagSwitchesBegin[];
 extern const char kFlagSwitchesEnd[];
 extern const char kFeedbackServer[];