Fix stats table on linux. There were two problems:...

chrome/app/chrome_dll_main.cc

Index: chrome/app/chrome_dll_main.cc
===================================================================
--- chrome/app/chrome_dll_main.cc	(revision 52678)
+++ chrome/app/chrome_dll_main.cc	(working copy)
@@ -413,6 +413,26 @@
 }
 #endif  // defined(OS_MACOSX)
 
+void InitializeStatsTable(base::ProcessId browser_pid,
+                          const CommandLine & parsed_command_line) {
+  // Initialize the Stats Counters table.  With this initialized,
+  // the StatsViewer can be utilized to read counters outside of
+  // Chrome.  These lines can be commented out to effectively turn
+  // counters 'off'.  The table is created and exists for the life
+  // of the process.  It is not cleaned up.
+  if (parsed_command_line.HasSwitch(switches::kEnableStatsTable) ||
+      parsed_command_line.HasSwitch(switches::kEnableBenchmarking)) {
+    // NOTIMPLEMENTED: we probably need to shut this down correctly to avoid
+    // leaking shared memory regions on posix platforms.
+    std::string statsfile =
+        StringPrintf("%s-%u", chrome::kStatsFilename,
+                     static_cast<unsigned int>(browser_pid));
+    StatsTable *stats_table = new StatsTable(statsfile,
+        chrome::kStatsMaxThreads, chrome::kStatsMaxCounters);
+    StatsTable::set_current(stats_table);
+  }
+}
+
 }  // namespace
 
 #if defined(OS_WIN)
@@ -556,8 +576,11 @@
     browser_pid =
         static_cast<base::ProcessId>(StringToInt(WideToASCII(channel_name)));
     DCHECK_NE(browser_pid, 0u);
-#else
+#elif defined(OS_MACOSX)
     browser_pid = base::GetCurrentProcId();
+#elif defined(OS_POSIX)
+    // On linux, we're in the zygote here; so we need the parent process' id.
+    browser_pid = base::GetParentProcessId(base::GetCurrentProcId());
 #endif
 
 #if defined(OS_POSIX)
@@ -618,22 +641,7 @@
     InitCrashProcessInfo();
 #endif  // OS_MACOSX
 
-  // Initialize the Stats Counters table.  With this initialized,
-  // the StatsViewer can be utilized to read counters outside of
-  // Chrome.  These lines can be commented out to effectively turn
-  // counters 'off'.  The table is created and exists for the life
-  // of the process.  It is not cleaned up.
-  // TODO(port): we probably need to shut this down correctly to avoid
-  // leaking shared memory regions on posix platforms.
-  if (parsed_command_line.HasSwitch(switches::kEnableStatsTable) ||
-      parsed_command_line.HasSwitch(switches::kEnableBenchmarking)) {
-    std::string statsfile =
-        StringPrintf("%s-%u", chrome::kStatsFilename,
-                     static_cast<unsigned int>(browser_pid));
-    StatsTable *stats_table = new StatsTable(statsfile,
-        chrome::kStatsMaxThreads, chrome::kStatsMaxCounters);
-    StatsTable::set_current(stats_table);
-  }
+  InitializeStatsTable(browser_pid, parsed_command_line);
 
   StatsScope<StatsCounterTimer>
       startup_timer(chrome::Counters::chrome_main());
@@ -796,6 +804,12 @@
       // line so update it here with the new version.
       const CommandLine& parsed_command_line =
         *CommandLine::ForCurrentProcess();
+
+      // The StatsTable must be initialized in each process; we already
+      // initialized for the browser process, now we need to initialize
+      // within the new processes as well.
+      InitializeStatsTable(browser_pid, parsed_command_line);

[Evan Martin, 2010/11/22 22:19:22]

Hey, remember this old change?  I am touching this code again for unrelated
reasons and I don't understand this.  We've already initialized the stats table
for the zygote process at L644, and ZygoteMain() will just fork(), so the
subprocess inherits the initialized table here.  Do you remember why you needed
to recreate it?

[Mike Belshe, 2010/11/22 22:30:52]

I can't recall exactly what was broken before - but we want the child to open
the shared memory segment separately from the parent.  Line 644 creates the
shared memory in the browser process, line 811 has each child process open it
and use it as a subscriber.  It seems like a fork should be sufficient, I forget
why that was not the case.

[Evan Martin, 2010/11/22 22:32:31]

Can you advise me how I can test whether my refactoring breaks this?  I run with
--enable-stats-table, and then check that [fill me in].

+
       MainFunctionParams main_params(parsed_command_line, sandbox_wrapper,
                                      &autorelease_pool);
       std::string process_type =