Mac: Create a pid->task_t mapping in the browser process.

base/process_util_mac.mm

 // Copyright (c) 2008 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.
 
 
 #include "base/process_util.h"
 
 #import <Cocoa/Cocoa.h>
 #include <crt_externs.h>
 #include <mach/mach.h>
@@ skipping 175 matching lines @@
 // general, so there doesn't really seem to be a way to do these (and spinning
 // up ps to fetch each stats seems dangerous to put in a base api for anyone to
 // call). Child processes ipc their port, so return something if available,
 // otherwise return 0.
 //
 bool ProcessMetrics::GetIOCounters(IoCounters* io_counters) const {
   return false;
 }
 
 static bool GetTaskInfo(mach_port_t task, task_basic_info_64* task_info_data) {
-  if (!task)
+  if (task == MACH_PORT_NULL)
     return false;
   mach_msg_type_number_t count = TASK_BASIC_INFO_64_COUNT;
   kern_return_t kr = task_info(task,
                                TASK_BASIC_INFO_64,
                                reinterpret_cast<task_info_t>(task_info_data),
                                &count);
   // Most likely cause for failure: |task| is a zombie.
   return kr == KERN_SUCCESS;
 }
 
@@ skipping 36 matching lines @@
   return true;
 }
 
 #define TIME_VALUE_TO_TIMEVAL(a, r) do {  \
   (r)->tv_sec = (a)->seconds;             \
   (r)->tv_usec = (a)->microseconds;       \
 } while (0)
 
 int ProcessMetrics::GetCPUUsage() {
   mach_port_t task = TaskForPid(process_);
-  if (!task)
+  if (task == MACH_PORT_NULL)
     return 0;
 
   kern_return_t kr;
 
   // TODO(thakis): Libtop doesn't use thread info. How can they get away
   // without it?
   task_thread_times_info thread_info_data;
   mach_msg_type_number_t thread_info_count = TASK_THREAD_TIMES_INFO_COUNT;
   kr = task_info(task,
                  TASK_THREAD_TIMES_INFO,
@@ skipping 46 matching lines @@
   int cpu = static_cast<int>((system_time_delta * 100 + time_delta / 2) /
                              (time_delta));
 
   last_system_time_ = task_time;
   last_time_ = time;
 
   return cpu;
 }
 
 mach_port_t ProcessMetrics::TaskForPid(ProcessHandle process) const {
-  mach_port_t task = 0;
+  mach_port_t task = MACH_PORT_NULL;
   if (port_provider_)
     task = port_provider_->TaskForPid(process_);
-  if (!task && process_ == getpid())
+  if (task == MACH_PORT_NULL && process_ == getpid())
     task = mach_task_self();
   return task;
 }
 
 // ------------------------------------------------------------------------
 
 // Bytes committed by the system.
 size_t GetSystemCommitCharge() {
   host_name_port_t host = mach_host_self();
   mach_msg_type_number_t count = HOST_VM_INFO_COUNT;
@@ skipping 98 matching lines @@
   CHECK(g_old_malloc && g_old_calloc && g_old_valloc && g_old_realloc)
       << "Failed to get system allocation functions.";
 
   default_zone->malloc = oom_killer_malloc;
   default_zone->calloc = oom_killer_calloc;
   default_zone->valloc = oom_killer_valloc;
   default_zone->realloc = oom_killer_realloc;
 }
 
 }  // namespace base