Make chrome.exe rendezvous with existing chrome process earlier.

chrome/app/chrome_exe_main_win.cc

Index: chrome/app/chrome_exe_main_win.cc
diff --git a/chrome/app/chrome_exe_main_win.cc b/chrome/app/chrome_exe_main_win.cc
index 237784d5649622f84f7821ae38db1fe21b19d090..aeb8cde39320b7394876a468f6eaa5f3fc15c18d 100644
--- a/chrome/app/chrome_exe_main_win.cc
+++ b/chrome/app/chrome_exe_main_win.cc
@@ -5,11 +5,18 @@
 #include <windows.h>
 #include <tchar.h>
 
+#include <string>
+
 #include "base/at_exit.h"
 #include "base/command_line.h"
+#include "base/files/file_path.h"
 #include "chrome/app/breakpad_win.h"
 #include "chrome/app/client_util.h"
 #include "chrome/app/metro_driver_win.h"
+#include "chrome/browser/chrome_process_finder_win.h"
+#include "chrome/browser/policy/policy_path_parser.h"
+#include "chrome/common/chrome_paths_internal.h"
+#include "chrome/common/chrome_switches.h"
 #include "content/public/app/startup_helper_win.h"
 #include "content/public/common/result_codes.h"
 #include "sandbox/win/src/sandbox_factory.h"
@@ -34,12 +41,53 @@ int RunChrome(HINSTANCE instance) {
   return rc;
 }
 
+// List of switches that it's safe to rendezvous early with.
+const std::string kFastStartSwitches[] = {

[grt (UTC plus 2), 2013/05/09 16:10:44]

this will create exit-time dtors, which is banned. see my suggestion in
ContainsNonFastStartFlag for a better way.

[koz (OOO until 15th September), 2013/05/10 01:46:48]

Done.

+  switches::kProfileDirectory,
+  switches::kShowAppList,
+};
+
+bool IsFastStartSwitch(const std::string& command_line_switch) {
+  for (size_t i = 0; i < arraysize(kFastStartSwitches); i++)
+    if (kFastStartSwitches[i] == command_line_switch)
+      return true;
+  return false;
+}
+
+bool ContainsNonFastStartFlag(CommandLine* command_line) {
+  const CommandLine::SwitchMap& switches = command_line->GetSwitches();

[grt (UTC plus 2), 2013/05/09 16:10:44]

i think you're better off with:
  static const char* const kFastStartSwitches[] = { ... };
  for (size_t i = 0; i < arraysize(kFastStartSwitches); ++i) {
    if (command_line->HasSwitch(kFastStartSwitches[i]))
      return true;
  }
  return false;
which gives you O(NlogM) rather than O(NM) and only creates/destroys one string
for each item in kFastStartSwitches.

[koz (OOO until 15th September), 2013/05/10 01:46:48]

I think the code you've given will return true iff the command line has at least
one switch in it from kFastStartSwitches, but the intention of that list is that
only command lines consisting solely of those switches are able to be
fast-started, ie: we need to check each flag in the command line against all the
flags in kFastStartSwitches. I've expanded on the comment to make this clearer.

[grt (UTC plus 2), 2013/05/10 16:53:04]

oops. i see. apologies for the bad suggestion.

+  for (CommandLine::SwitchMap::const_iterator it = switches.begin();
+       it != switches.end(); it++) {
+    if (!IsFastStartSwitch(it->first))
+      return true;
+  }
+  return false;
+}
+
+bool AttemptFastNotify(CommandLine* command_line) {
+  if (ContainsNonFastStartFlag(command_line))
+    return false;
+
+  base::FilePath user_data_dir;
+  if (!chrome::GetDefaultUserDataDirectory(&user_data_dir))
+    return false;
+  policy::path_parser::CheckUserDataDirPolicy(&user_data_dir);
+
+  HWND chrome = chrome::FindRunningChromeWindow(user_data_dir);
+  if (chrome && chrome::AttemptToNotifyRunningChrome(chrome))

[grt (UTC plus 2), 2013/05/09 16:10:44]

return chrome && chrome::AttemptToNotifyRunningChrome(chrome);

[koz (OOO until 15th September), 2013/05/10 01:46:48]

Done.

+    return true;
+  return false;
+}
+
 int APIENTRY wWinMain(HINSTANCE instance, HINSTANCE prev, wchar_t*, int) {
   // Initialize the commandline singleton from the environment.
   CommandLine::Init(0, NULL);
   // The exit manager is in charge of calling the dtors of singletons.
   base::AtExitManager exit_manager;
 
+  if (AttemptFastNotify(CommandLine::ForCurrentProcess()))
+    return 0;
+
   MetroDriver metro_driver;
   if (metro_driver.in_metro_mode())
     return metro_driver.RunInMetro(instance, &RunChrome);