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

chrome/browser/process_singleton.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_PROCESS_SINGLETON_H_
 #define CHROME_BROWSER_PROCESS_SINGLETON_H_
 
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
@@ skipping 31 matching lines @@
 // each other.  It is named according to the user data directory, so
 // we can be sure that no more than one copy of the application can be
 // running at once with a given data directory.
 //
 // Implementation notes:
 // - the Windows implementation uses an invisible global message window;
 // - the Linux implementation uses a Unix domain socket in the user data dir.
 
 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,
+    REMOTE_PROCESS_SHUTTING_DOWN = 6,
+    PROFILE_UNLOCKED = 7,
+    PROFILE_UNLOCKED_BEFORE_KILL = 8,
+    SAME_BROWSER_INSTANCE = 9,
+    SAME_BROWSER_INSTANCE_BEFORE_KILL = 10,
+    FAILED_TO_EXTRACT_PID = 11,
+    INVALID_LOCK_FILE = 12,
+    ORPHANED_LOCK_FILE = 13,
+#endif
+    REMOTE_PROCESS_INTERACTION_RESULT_COUNT = 14

[gab, 2017/05/15 16:58:39]

Do not give an explicit number to the count, that way it will grow automatically
if more items are added (and it will also be the appropriate size per platform)

[Alexey Seren, 2017/05/15 19:20:25]

I think that COUNT should have one value on each platform because Bucket count
for histogram is calculated as COUNT + 1
One value of Bucket count for different platforms can be significant for server
that collects and processes this histogram for all platforms.

[gab, 2017/05/15 20:13:05]

AFAIK, UMA doesn't process "count", it's only used client-side to know how many
buckets are required when aggregating the stats.

If this wasn't the case the server would choke when the count changes later and
different versions of chrome report different counts anyways.

In that light, I still insist that we remove the count as it reinforces what you
mentioned which isn't correct in practice.

[Alexey Seren, 2017/05/16 05:30:38]

Acknowledged.
Ok, you are right. Thank you for the explanation!

+  };
+
   // Logged as histograms, do not modify these values.
   enum NotifyResult {
     PROCESS_NONE = 0,
     PROCESS_NOTIFIED = 1,
     PROFILE_IN_USE = 2,
     LOCK_ERROR = 3,
     LAST_VALUE = LOCK_ERROR
   };
 
   static constexpr int kNumNotifyResults = LAST_VALUE + 1;
@@ skipping 26 matching lines @@
   // NOTE: Most callers should generally prefer NotifyOtherProcessOrCreate() to
   // this method, only callers for whom failure is preferred to notifying
   // another process should call this directly.
   bool Create();
 
   // Clear any lock state during shutdown.
   void Cleanup();
 
 #if defined(OS_POSIX) && !defined(OS_ANDROID)
   static void DisablePromptForTesting();
+  static void SkipIsChromeProcessCheckForTesting();
 #endif
 #if defined(OS_WIN)
   // Called to query whether to kill a hung browser process that has visible
   // windows. Return true to allow killing the hung process.
   using ShouldKillRemoteProcessCallback = base::Callback<bool()>;
   void OverrideShouldKillRemoteProcessCallbackForTesting(
       const ShouldKillRemoteProcessCallback& display_dialog_callback);
 #endif
 
  protected:
@@ skipping 70 matching lines @@
   // Helper class for linux specific messages.  LinuxWatcher is ref counted
   // because it posts messages between threads.
   class LinuxWatcher;
   scoped_refptr<LinuxWatcher> watcher_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(ProcessSingleton);
 };
 
 #endif  // CHROME_BROWSER_PROCESS_SINGLETON_H_