Use process_singleton_linux on Mac.

chrome/browser/process_singleton_posix.cc

Index: chrome/browser/process_singleton_posix.cc
diff --git a/chrome/browser/process_singleton_linux.cc b/chrome/browser/process_singleton_posix.cc
similarity index 99%
rename from chrome/browser/process_singleton_linux.cc
rename to chrome/browser/process_singleton_posix.cc
index 8038afe45e44da34a572e7532aa1565080819217..b68d25fafedf0e94df5240d8048db46d447377b7 100644
--- a/chrome/browser/process_singleton_linux.cc
+++ b/chrome/browser/process_singleton_posix.cc
@@ -74,7 +74,6 @@
 #include "base/threading/platform_thread.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
-#include "chrome/browser/ui/process_singleton_dialog_linux.h"
 #include "chrome/common/chrome_constants.h"
 #include "content/public/browser/browser_thread.h"
 #include "grit/chromium_strings.h"
@@ -82,6 +81,10 @@
 #include "net/base/net_util.h"
 #include "ui/base/l10n/l10n_util.h"
 
+#if defined(OS_LINUX)
+#include "chrome/browser/ui/process_singleton_dialog_linux.h"
+#endif
+
 #if defined(TOOLKIT_GTK)
 #include <gdk/gdk.h>
 #endif
@@ -301,14 +304,17 @@ bool DisplayProfileInUseError(const base::FilePath& lock_path,
                               const std::string& hostname,
                               int pid) {
   base::string16 error = l10n_util::GetStringFUTF16(
-      IDS_PROFILE_IN_USE_LINUX,
+      IDS_PROFILE_IN_USE_POSIX,
       base::IntToString16(pid),
       base::ASCIIToUTF16(hostname));
+  LOG(ERROR) << base::SysWideToNativeMB(base::UTF16ToWide(error)).c_str();
+  if (!g_disable_prompt) {
+#if defined(OS_LINUX)
   base::string16 relaunch_button_text = l10n_util::GetStringUTF16(
       IDS_PROFILE_IN_USE_LINUX_RELAUNCH);
-  LOG(ERROR) << base::SysWideToNativeMB(base::UTF16ToWide(error)).c_str();
-  if (!g_disable_prompt)
-    return ShowProcessSingletonDialog(error, relaunch_button_text);
+  return ShowProcessSingletonDialog(error, relaunch_button_text);

[tapted, 2014/04/08 17:56:44]

Does this need an implementation on mac as well? I guess a log message is not so
different to what users get now.. but does the linux singleton have the same
assurance/recovery for a dangling profile lock?

That is, currently there's a good guarantee on mac that Force-Quitting Chrome
will make the 'Unable to obtain profile lock' error go away. Is there any flow
where that could leave a dangling lock, requiring user intervention? (like, user
connects to a different network and their hostname changes, causing the logic to
think an old process is on a different computer and not auto-kill the currently
running (or dead) process?)

Also, what's an example string you get on Mac?

[jackhou1, 2014/04/14 04:12:10]

It's actually less common than what users get now. At the moment, a log message
occurs whenever you start another chrome process with the same UDD. After this
change, that case will just work. The message here only occurs if the existing
process is not running on the same host.
 
Interesting, I think this case could happen on linux too, except it would let
the user decide to usurp the lock. I wonder if we could use something more
constant than hostname instead?
From the unit test:
The profile appears to be in use by another Chromium process (1234) on another
computer (FAKEFOOHOST). Chromium has locked the profile so that it doesn't get
corrupted. If you are sure no other processes are using this profile, you can
unlock the profile and relaunch Chromium.

[mattm, 2014/04/17 21:44:54]

I'm not sure about osx, but linux doesn't normally change the hostname on a
network change.

+#endif
+  }
   return false;
 }