[Mac] Add a perf test that counts the number of Mach ports in the browser.

chrome/common/automation_messages_internal.h

Index: chrome/common/automation_messages_internal.h
diff --git a/chrome/common/automation_messages_internal.h b/chrome/common/automation_messages_internal.h
index 08040b3ba7a401db4dc911e7b6c446eed035d381..89be8909d6e84ab892bf5a5f3fde6c85c93e2657 100644
--- a/chrome/common/automation_messages_internal.h
+++ b/chrome/common/automation_messages_internal.h
@@ -1506,6 +1506,11 @@ IPC_SYNC_MESSAGE_CONTROL2_1(AutomationMsg_AppendBackgroundTab,
                             GURL,
                             int)
 
+// Used on Mac OS X to read the number of active Mach ports used in the browser
+// process.
+IPC_SYNC_MESSAGE_CONTROL0_1(AutomationMsg_GetMachPortCount,
+                            int /* number of Mach ports */)

[cmp, 2012/01/23 21:20:51]

iirc new messages should be added at the end of this file, otherwise testing
against the reference build will break.  don't break that unless absolutely
necessary. :)  (see line 12)

you should add running your test using the current reference build as one of the
verifications for your CL so we know what to expect.

your change will most likely eventually require updating the reference build.  i
would treat that as a separate process and so design this change as being able
to land without also needing an immediate reference build update.

it would be even better if you can find a way to not need a reference build
change at all.  or if you're adding a new type of data, thinking ahead to how
other kinds of this data may be added in the future without requiring a
reference build change.

[Robert Sesek, 2012/01/23 21:58:41]

I *think* this is the right place, based on line 1538-41.
OK. The reference build will likely contain a bug for which this test is
protecting from regressions. Its numbers will be higher than what's reported by
trunk.

[cmp, 2012/01/23 22:20:56]

Okay, sgtm.
Okay, since you won't need to run this test in the reference build (as you say
later it's more like sizes) let's only make sure that, say, the PageCyclerTest
will still work in the reference build after your change.  Other tests may have
broken but it's too hard to tell right now which ones, so just focus on running
PageCyclerTest.

+
 // Browser -> renderer messages.
 
 // Requests a snapshot.