Added histograms on process singleton create when remote process exists and we cannot notify it

chrome/browser/process_singleton.h

Index: chrome/browser/process_singleton.h
diff --git a/chrome/browser/process_singleton.h b/chrome/browser/process_singleton.h
index 96a9bf65f42d2cfab301a10573b25739e7e05a4e..3bb5ad240c01f4a8d76db23939989992edc73ac1 100644
--- a/chrome/browser/process_singleton.h
+++ b/chrome/browser/process_singleton.h
@@ -49,6 +49,40 @@ class CommandLine;
 
 class ProcessSingleton : public base::NonThreadSafe {
  public:
+  // Used to send the reason of remote hang process termination as histogram.
+  enum RemoteHungProcessTerminateReason {
+#if defined(OS_WIN)
+    USER_ACCEPTED_TERMINATION = 1,
+    NO_VISIBLE_WINDOW_FOUND = 2,
+#elif defined(OS_POSIX)
+    NOTIFY_ATTEMPTS_EXCEEDED = 3,
+    SOCKET_WRITE_FAILED = 4,
+    SOCKET_READ_FAILED = 5,
+#endif
+    REMOTE_HUNG_PROCESS_TERMINATE_REASON_COUNT = 6
+  };
+
+  // Used to send the result of interaction with remote process as histograms in
+  // case when remote process influences on start.
+  enum RemoteProcessInteractionResult {
+    TERMINATE_SUCCEEDED = 0,
+    TERMINATE_FAILED = 1,
+    REMOTE_PROCESS_NOT_FOUND = 2,
+#if defined(OS_WIN)
+    TERMINATE_WAIT_TIMEOUT = 3,
+    RUNNING_PROCESS_NOTIFY_ERROR = 4,
+#elif defined(OS_POSIX)
+    TERMINATE_NOT_ENOUGH_PERMISSIONS = 5,

[gab, 2017/05/12 18:40:59]

Why are some terminate histograms here instead of under
RemoteHungProcessTerminateReason?

[Alexey Seren, 2017/05/15 08:40:48]

"RemoteProcessInteractionResult" histogram tracks what happened if process
starts in presence of existing browsers.
"RemoteHungProcessTerminateReason" histogram track the reason why we have tried
to terminate remote process.

TERMINATE_NOT_ENOUGH_PERMISSIONS indicated what happened. It means that we have
tried to terminate remote process but have no permissions for it.

+    REMOTE_PROCESS_SHUTTING_DOWN = 6,
+    PROFILE_UNLOCKED = 7,
+    FAILED_TO_EXTRACT_PID = 8,
+    INVALID_LOCK_FILE = 9,
+    ORPHANED_LOCK_FILE = 10,
+    SAME_BROWSER_INSTANCE = 11,
+#endif
+    REMOTE_PROCESS_INTERACTION_RESULT_COUNT = 12
+  };
+
   // Logged as histograms, do not modify these values.
   enum NotifyResult {
     PROCESS_NONE = 0,