Migrate ProcessesEventRouter to the new task manager

chrome/browser/extensions/api/processes/processes_api.cc

 // 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.
 
 #include "chrome/browser/extensions/api/processes/processes_api.h"
 
-#include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
-#include <utility>
-
-#include "base/callback.h"
-#include "base/json/json_writer.h"
+
 #include "base/lazy_instance.h"
-#include "base/location.h"
-#include "base/metrics/histogram.h"
-#include "base/single_thread_task_runner.h"
+#include "base/metrics/histogram_macros.h"
+#include "base/process/process.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/thread_task_runner_handle.h"
-#include "base/values.h"
-#include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/extensions/api/tabs/tabs_constants.h"
-#include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_tab_util.h"
 #include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/task_manager/resource_provider.h"
-#include "chrome/browser/task_manager/task_manager.h"
+#include "chrome/browser/task_management/task_manager_interface.h"
 #include "chrome/common/extensions/api/processes.h"
-#include "content/public/browser/browser_context.h"
-#include "content/public/browser/notification_details.h"
-#include "content/public/browser/notification_service.h"
-#include "content/public/browser/notification_source.h"
-#include "content/public/browser/notification_types.h"
+#include "content/public/browser/browser_child_process_host.h"
+#include "content/public/browser/child_process_data.h"
+
 #include "content/public/browser/render_process_host.h"
-#include "content/public/browser/render_view_host.h"
-#include "content/public/browser/render_widget_host.h"
-#include "content/public/browser/render_widget_host_iterator.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/common/child_process_host.h"
 #include "content/public/common/result_codes.h"
-#include "extensions/browser/event_router.h"
-#include "extensions/browser/extension_function_registry.h"
-#include "extensions/browser/extension_function_util.h"
 #include "extensions/common/error_utils.h"
+#include "third_party/WebKit/public/web/WebCache.h"
 
 namespace extensions {
 
 namespace errors {
 const char kNotAllowedToTerminate[] = "Not allowed to terminate process: *.";
 const char kProcessNotFound[] = "Process not found: *.";
-const char kInavlidArgument[] = "Invalid argument: *.";
+const char kInvalidArgument[] = "Invalid argument: *.";
 }  // namespace errors
 
 namespace {
 
-#if defined(ENABLE_TASK_MANAGER)
+base::LazyInstance<BrowserContextKeyedAPIFactory<ProcessesAPI> >
+    g_processes_api_factory = LAZY_INSTANCE_INITIALIZER;
+
+int64_t GetRefreshTypesFlagOnlyEssentialData() {
+  // This is the only non-optional data in the Process as defined by the API in
+  // processes.idl.
+  return task_management::REFRESH_TYPE_NACL;
+}
+
+// This does not include memory. The memory refresh flag will only be added once
+// a listener to OnUpdatedWithMemory event is added.
+int64_t GetRefreshTypesFlagIncludeOptionalData() {
+  return GetRefreshTypesFlagOnlyEssentialData() |
+      task_management::REFRESH_TYPE_CPU |
+      task_management::REFRESH_TYPE_NETWORK_USAGE |
+      task_management::REFRESH_TYPE_SQLITE_MEMORY |
+      task_management::REFRESH_TYPE_V8_MEMORY |
+      task_management::REFRESH_TYPE_WEBCACHE_STATS;
+}
 
 scoped_ptr<api::processes::Cache> CreateCacheData(
     const blink::WebCache::ResourceTypeStat& stat) {
-  scoped_ptr<api::processes::Cache> cache(new api::processes::Cache());

[Devlin, 2016/03/03 23:12:43]

revert this change

[afakhry, 2016/03/08 01:37:29]

Done.

+  scoped_ptr<api::processes::Cache> cache(new api::processes::Cache);
   cache->size = static_cast<double>(stat.size);
   cache->live_size = static_cast<double>(stat.liveSize);
   return cache;
 }
 
-api::processes::ProcessType GetProcessType(TaskManagerModel* model,
-                                           int index) {
-  // Determine process type.
-  task_manager::Resource::Type resource_type = model->GetResourceType(index);
-  switch (resource_type) {
-    case task_manager::Resource::BROWSER:
+api::processes::ProcessType GetProcessType(
+    task_management::Task::Type task_type) {
+  switch (task_type) {
+    case task_management::Task::BROWSER:
       return api::processes::PROCESS_TYPE_BROWSER;
 
-    case task_manager::Resource::RENDERER:
+    case task_management::Task::RENDERER:
       return api::processes::PROCESS_TYPE_RENDERER;
 
-    case task_manager::Resource::EXTENSION:
-    case task_manager::Resource::GUEST:
+    case task_management::Task::EXTENSION:
+    case task_management::Task::GUEST:
       return api::processes::PROCESS_TYPE_EXTENSION;
 
-    case task_manager::Resource::NOTIFICATION:
-      return api::processes::PROCESS_TYPE_NOTIFICATION;
-
-    case task_manager::Resource::PLUGIN:
+    case task_management::Task::PLUGIN:
       return api::processes::PROCESS_TYPE_PLUGIN;
 
-    case task_manager::Resource::WORKER:
+    case task_management::Task::WORKER:
       return api::processes::PROCESS_TYPE_WORKER;
 
-    case task_manager::Resource::NACL:
+    case task_management::Task::NACL:
       return api::processes::PROCESS_TYPE_NACL;
 
-    case task_manager::Resource::UTILITY:
+    case task_management::Task::UTILITY:
       return api::processes::PROCESS_TYPE_UTILITY;
 
-    case task_manager::Resource::GPU:
+    case task_management::Task::GPU:
       return api::processes::PROCESS_TYPE_GPU;
 
-    case task_manager::Resource::ZYGOTE:
-    case task_manager::Resource::SANDBOX_HELPER:
-    case task_manager::Resource::UNKNOWN:
+    case task_management::Task::UNKNOWN:
+    case task_management::Task::ARC:
+    case task_management::Task::SANDBOX_HELPER:
+    case task_management::Task::ZYGOTE:
       return api::processes::PROCESS_TYPE_OTHER;
   }
 
-  NOTREACHED() << "Unknown resource type.";
+  NOTREACHED() << "Unknown task type.";
   return api::processes::PROCESS_TYPE_NONE;
 }
 
-void FillTabsForProcess(int process_id, api::processes::Process* out_process) {
+// Fills |out_process| with the data of the process in which the task with |id|
+// is running. If |include_optional| is true, this function will fill the
+// optional fields in |api::processes::Process| except for |private_memory|,
+// which should be filled later if needed.
+void FillProcessData(
+    task_management::TaskId id,
+    task_management::TaskManagerInterface* task_manager,
+    bool include_optional,
+    api::processes::Process* out_process) {
   DCHECK(out_process);
 
-  // The tabs list only makes sense for render processes, so if we don't find
-  // one, just return the empty list.
-  content::RenderProcessHost* rph =
-      content::RenderProcessHost::FromID(process_id);
-  if (!rph)
-    return;
-
-  int tab_id = -1;
-  // We need to loop through all the RVHs to ensure we collect the set of all
-  // tabs using this renderer process.
-  scoped_ptr<content::RenderWidgetHostIterator> widgets(
-      content::RenderWidgetHost::GetRenderWidgetHosts());
-  while (content::RenderWidgetHost* widget = widgets->GetNextHost()) {
-    if (widget->GetProcess()->GetID() != process_id)
-      continue;
-
-    content::RenderViewHost* host = content::RenderViewHost::From(widget);
-    content::WebContents* contents =
-        content::WebContents::FromRenderViewHost(host);
-    if (contents) {
-      tab_id = ExtensionTabUtil::GetTabId(contents);
-      if (tab_id != -1)
-        out_process->tabs.push_back(tab_id);
-    }
-  }
-}
-
-// This function fills |out_process| with the data of the process with
-// |process_id|. For memory details, which are not added by this function,
-// the callers need to use AddMemoryDetails.
-void FillProcessData(int process_id,
-                     TaskManagerModel* model,
-                     int index,
-                     bool include_optional,
-                     api::processes::Process* out_process) {
-  DCHECK(out_process);
-
-  out_process->id = process_id;
-  out_process->os_process_id = model->GetProcessId(index);
-  out_process->type = GetProcessType(model, index);
-  out_process->title = base::UTF16ToUTF8(model->GetResourceTitle(index));
-  out_process->profile =
-      base::UTF16ToUTF8(model->GetResourceProfileName(index));
-  out_process->nacl_debug_port = model->GetNaClDebugStubPort(index);
-
-  FillTabsForProcess(process_id, out_process);
+  out_process->id = task_manager->GetChildProcessUniqueId(id);
+  out_process->os_process_id = task_manager->GetProcessId(id);
+  out_process->type = GetProcessType(task_manager->GetType(id));
+  out_process->profile = base::UTF16ToUTF8(task_manager->GetProfileName(id));
+  out_process->nacl_debug_port = task_manager->GetNaClDebugStubPort(id);
+
+  // Collect the tab IDs of all the tasks sharing this renderer if any.
+  const task_management::TaskIdList tasks_on_process =
+      task_manager->GetIdsOfTasksSharingSameProcess(id);
+  for (const auto& task_id : tasks_on_process) {
+    linked_ptr<api::processes::TaskInfo> task_info(
+        new api::processes::TaskInfo);

[Devlin, 2016/03/03 23:12:43]

nit: explicit ctor

[afakhry, 2016/03/08 01:37:29]

Done.

+    task_info->title = base::UTF16ToUTF8(task_manager->GetTitle(task_id));
+    const int tab_id = task_manager->GetTabId(task_id);
+    if (tab_id != -1)
+      task_info->tab_id.reset(new int(tab_id));
+
+    out_process->tasks.push_back(task_info);
+  }
 
   // If we don't need to include the optional properties, just return now.
   if (!include_optional)
     return;
 
-  out_process->cpu.reset(new double(model->GetCPUUsage(index)));
-
-  size_t mem = 0;
-  if (model->GetV8Memory(index, &mem)) {
+  out_process->cpu.reset(new double(task_manager->GetCpuUsage(id)));
+
+  out_process->network.reset(new double(static_cast<double>(
+      task_manager->GetProcessTotalNetworkUsage(id))));
+
+  int64_t v8_allocated;

[Devlin, 2016/03/03 23:12:43]

initialize these

[afakhry, 2016/03/08 01:37:29]

Done.

+  int64_t v8_used;
+  if (task_manager->GetV8Memory(id, &v8_allocated, & v8_used)) {

[Devlin, 2016/03/03 23:12:43]

nit: no space between & and v8_used (would git cl format catch this?)

[afakhry, 2016/03/08 01:37:29]

Done. Yes it does catch it.

     out_process->js_memory_allocated.reset(new double(static_cast<double>(
-        mem)));
-  }
-
-  if (model->GetV8MemoryUsed(index, &mem))
-    out_process->js_memory_used.reset(new double(static_cast<double>(mem)));
-
-  if (model->GetSqliteMemoryUsedBytes(index, &mem))
-    out_process->sqlite_memory.reset(new double(static_cast<double>(mem)));
+        v8_allocated)));
+    out_process->js_memory_used.reset(new double(static_cast<double>(v8_used)));
+  }
+
+  const int64_t sqlite_bytes = task_manager->GetSqliteMemoryUsed(id);
+  if (sqlite_bytes != -1) {
+    out_process->sqlite_memory.reset(new double(static_cast<double>(
+        sqlite_bytes)));
+  }
 
   blink::WebCache::ResourceTypeStats cache_stats;
-  if (model->GetWebCoreCacheStats(index, &cache_stats)) {
+  if (task_manager->GetWebCacheStats(id, &cache_stats)) {
     out_process->image_cache = CreateCacheData(cache_stats.images);
     out_process->script_cache = CreateCacheData(cache_stats.scripts);
     out_process->css_cache = CreateCacheData(cache_stats.cssStyleSheets);
   }
-
-  // Network is reported by the TaskManager per resource (tab), not per
-  // process, therefore we need to iterate through the group of resources
-  // and aggregate the data.
-  int64_t net = 0;
-  int length = model->GetGroupRangeForResource(index).second;
-  for (int i = 0; i < length; ++i)
-    net += model->GetNetworkUsage(index + i);
-  out_process->network.reset(new double(static_cast<double>(net)));
-}
-
-// Since memory details are expensive to gather, we don't do it by default.
-// This function is a helper to add memory details data to an existing
-// Process object |out_process|.
-void AddMemoryDetails(TaskManagerModel* model,
-                      int index,
-                      api::processes::Process* out_process) {
-  DCHECK(out_process);
-
-  size_t mem;
-  int64_t pr_mem =
-      model->GetPrivateMemory(index, &mem) ? static_cast<int64_t>(mem) : -1;
-  out_process->private_memory.reset(new double(static_cast<double>(pr_mem)));
-}
-
-#endif  // defined(ENABLE_TASK_MANAGER)
+}
 
 }  // namespace
 
+////////////////////////////////////////////////////////////////////////////////
+// ProcessesEventRouter:
+////////////////////////////////////////////////////////////////////////////////
+
 ProcessesEventRouter::ProcessesEventRouter(content::BrowserContext* context)
-    : browser_context_(context), listeners_(0), task_manager_listening_(false) {
-#if defined(ENABLE_TASK_MANAGER)
-  model_ = TaskManager::GetInstance()->model();
-  model_->AddObserver(this);
-
-  registrar_.Add(this, content::NOTIFICATION_RENDER_WIDGET_HOST_HANG,
-      content::NotificationService::AllSources());
-  registrar_.Add(this, content::NOTIFICATION_RENDERER_PROCESS_CLOSED,
-      content::NotificationService::AllSources());
-#endif  // defined(ENABLE_TASK_MANAGER)
+    : task_management::TaskManagerObserver(
+          base::TimeDelta::FromSeconds(1),

[Devlin, 2016/03/03 23:12:43]

If we don't have any listeners for OnUpdated[WithMemory], won't this cause a
good deal of extra work for the task manager?  Could we instead wait until we
have a listener for OnUpdated and set the refresh time then?  (Optionally
setting it for an obscenely long time here)

[afakhry, 2016/03/08 01:37:29]

True. This doesn't add an observer to the task manager yet. It just sets up this
observer with its default settings. GetRefreshTypesFlagIncludeOptionalData()
doesn't include the memory refresh flag. ProcessesEventRouter::ListenerAdded()
is where we start observing the task manager and add the memory refresh flag if
a listener is interested in OnUpdatedWithMemory().

[Devlin, 2016/03/08 21:27:22]

Right.  The case I'm trying to defend against is that an extension adds a
listener for, e.g., onProcessCreated.  When that happens, we add this as an
observer to the TM.  But if that's the only listener, there's no reason to make
the TM regenerate the metrics for all processes, when all we really need is the
onCreated signal - but we'd still have it update every second.  It'd be good to
only force the TM to refresh all the metrics if we have a consumer for those.

[Devlin, 2016/03/09 15:16:12]

Looks like you missed this one?

[afakhry, 2016/03/09 18:46:36]

Yes, I did. Thanks for the reminder. All events
onCreated/onUpdated/onUpdatedWithMemory/onUnresponsive require sending some
stats about the process. The only event 'onExited' doesn't. But I see your point
now. Please take a look at the way things are now. If the refresh flags are set
to REFRESH_TYPE_NONE, then the task manager refresh will essentially do nothing.

+          GetRefreshTypesFlagIncludeOptionalData()),
+      browser_context_(context),
+      listeners_(0) {
 }
 
 ProcessesEventRouter::~ProcessesEventRouter() {
-#if defined(ENABLE_TASK_MANAGER)
-  registrar_.Remove(this, content::NOTIFICATION_RENDER_WIDGET_HOST_HANG,
-      content::NotificationService::AllSources());
-  registrar_.Remove(this, content::NOTIFICATION_RENDERER_PROCESS_CLOSED,
-      content::NotificationService::AllSources());
-
-  if (task_manager_listening_)
-    model_->StopListening();
-
-  model_->RemoveObserver(this);
-#endif  // defined(ENABLE_TASK_MANAGER)
+  if (observed_task_manager()) {
+    task_management::TaskManagerInterface::GetTaskManager()->RemoveObserver(
+        this);
+  }
 }
 
 void ProcessesEventRouter::ListenerAdded() {
-#if defined(ENABLE_TASK_MANAGER)
-  // The task manager has its own ref count to balance other callers of
-  // StartUpdating/StopUpdating.
-  model_->StartUpdating();
-#endif  // defined(ENABLE_TASK_MANAGER)
-  ++listeners_;
+  // Do we need to update memory usage?
+  if (HasEventListeners(api::processes::OnUpdatedWithMemory::kEventName))
+    AddRefreshType(task_management::REFRESH_TYPE_MEMORY);
+
+  if (listeners_++ == 0) {
+    // The first listener to be added.
+    task_management::TaskManagerInterface::GetTaskManager()->AddObserver(this);
+  }
 }
 
 void ProcessesEventRouter::ListenerRemoved() {
-  DCHECK_GT(listeners_, 0);
-  --listeners_;
-#if defined(ENABLE_TASK_MANAGER)
-  // The task manager has its own ref count to balance other callers of
-  // StartUpdating/StopUpdating.
-  model_->StopUpdating();
-#endif  // defined(ENABLE_TASK_MANAGER)
-}
-
-void ProcessesEventRouter::StartTaskManagerListening() {
-#if defined(ENABLE_TASK_MANAGER)
-  if (!task_manager_listening_) {
-    model_->StartListening();
-    task_manager_listening_ = true;
-  }
-#endif  // defined(ENABLE_TASK_MANAGER)
-}
-
-void ProcessesEventRouter::Observe(
-    int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
-
-  switch (type) {
-    case content::NOTIFICATION_RENDER_WIDGET_HOST_HANG:
-      ProcessHangEvent(
-          content::Source<content::RenderWidgetHost>(source).ptr());
-      break;
-    case content::NOTIFICATION_RENDERER_PROCESS_CLOSED:
-      ProcessClosedEvent(
-          content::Source<content::RenderProcessHost>(source).ptr(),
-          content::Details<content::RenderProcessHost::RendererClosedDetails>(
-              details).ptr());
-      break;
-    default:
-      NOTREACHED() << "Unexpected observe of type " << type;
-  }
-  return;
-}
-
-void ProcessesEventRouter::OnItemsAdded(int start, int length) {
-#if defined(ENABLE_TASK_MANAGER)
-  DCHECK_EQ(length, 1);
+  // No more listeners for memory usage?
+  if (!HasEventListeners(api::processes::OnUpdatedWithMemory::kEventName))
+    RemoveRefreshType(task_management::REFRESH_TYPE_MEMORY);
+
+  if (--listeners_ == 0) {
+    // Last listener to be removed.
+    task_management::TaskManagerInterface::GetTaskManager()->RemoveObserver(
+        this);
+  }
+}
+
+void ProcessesEventRouter::OnTaskAdded(task_management::TaskId id) {
   if (!HasEventListeners(api::processes::OnCreated::kEventName))
     return;
 
-  // If the item being added is not the first one in the group, find the base
-  // index and use it for retrieving the process data.
-  if (!model_->IsResourceFirstInGroup(start))
-    start = model_->GetGroupIndexForResource(start);
+  // Is this the first task to be created on the process and hence its creation
+  // corresponds to the creation of the process?
+  if (observed_task_manager()->GetNumberOfTasksOnSameProcess(id) != 1)
+    return;
+
+  // Ignore tasks that don't have a valid child process host ID like ARC
+  // processes, as well as the browser process (onCreate() shouldn't report the
+  // creation of the browser process).
+  const int child_process_host_id =
+      observed_task_manager()->GetChildProcessUniqueId(id);
+  if (child_process_host_id == content::ChildProcessHost::kInvalidUniqueID ||
+      child_process_host_id == 0) {
+    return;
+  }
 
   api::processes::Process process;
-  FillProcessData(model_->GetUniqueChildProcessId(start), model_, start,
-                  false /* include_optional */, &process);
+  FillProcessData(id, observed_task_manager(), false, &process);
   DispatchEvent(events::PROCESSES_ON_CREATED,
                 api::processes::OnCreated::kEventName,
                 api::processes::OnCreated::Create(process));
-#endif  // defined(ENABLE_TASK_MANAGER)
-}
-
-void ProcessesEventRouter::OnItemsChanged(int start, int length) {
-#if defined(ENABLE_TASK_MANAGER)
-  // If we don't have any listeners, return immediately.
-  if (listeners_ == 0)
-    return;
-
-  if (!model_)
-    return;
-
-  // We need to know which type of onUpdated events to fire and whether to
-  // collect memory or not.
-  bool updated = HasEventListeners(api::processes::OnUpdated::kEventName);
-  bool updated_memory =
+}
+
+void ProcessesEventRouter::OnTaskToBeRemoved(task_management::TaskId id) {
+  if (!HasEventListeners(api::processes::OnExited::kEventName))
+    return;
+
+  // Is this the last task to be removed from the process, and hence its removal

[Devlin, 2016/03/03 23:12:43]

Common code between this and OnTaskAdded could be pulled out.

[afakhry, 2016/03/08 01:37:29]

Done.

+  // corresponds to the termination of the process?
+  if (observed_task_manager()->GetNumberOfTasksOnSameProcess(id) != 1)
+    return;
+
+  // Ignore tasks that don't have a valid child process host ID like ARC
+  // processes, as well as the browser process (onExited() shouldn't report the
+  // exit of the browser process).
+  const int child_process_host_id =
+      observed_task_manager()->GetChildProcessUniqueId(id);
+  if (child_process_host_id == content::ChildProcessHost::kInvalidUniqueID ||
+      child_process_host_id == 0) {
+    return;
+  }
+
+  int exit_code = 0;
+  base::TerminationStatus status = base::TERMINATION_STATUS_STILL_RUNNING;
+  observed_task_manager()->GetTerminationStatus(id, &status, &exit_code);
+
+  DispatchEvent(events::PROCESSES_ON_EXITED,
+                api::processes::OnExited::kEventName,
+                api::processes::OnExited::Create(child_process_host_id,
+                                                 status,
+                                                 exit_code));
+}
+
+void ProcessesEventRouter::OnTasksRefreshedWithBackgroundCalculations(
+    const task_management::TaskIdList& task_ids) {
+  const bool has_on_updated_listeners =
+      HasEventListeners(api::processes::OnUpdated::kEventName);
+  const bool has_on_updated_with_memory_listeners =
       HasEventListeners(api::processes::OnUpdatedWithMemory::kEventName);
-  if (!updated && !updated_memory)
-    return;
-
+
+  if (!has_on_updated_listeners && !has_on_updated_with_memory_listeners)
+    return;
+
+  // Get the data of tasks sharing the same process only once.
+  std::set<base::ProcessId> seen_processes;
   base::DictionaryValue processes_dictionary;
-  for (int i = start; i < start + length; ++i) {
-    if (model_->IsResourceFirstInGroup(i)) {
-      int id = model_->GetUniqueChildProcessId(i);
-      api::processes::Process process;
-      FillProcessData(id, model_, i, true /* include_optional */, &process);
-      if (updated_memory)
-        AddMemoryDetails(model_, i, &process);
-      processes_dictionary.Set(base::IntToString(id), process.ToValue());
+  for (const auto& task_id : task_ids) {
+    // We are not interested in tasks, but rather the processes on which they
+    // run.
+    const base::ProcessId proc_id =
+        observed_task_manager()->GetProcessId(task_id);
+    if (seen_processes.count(proc_id))
+      continue;
+
+    const int child_process_host_id =
+        observed_task_manager()->GetChildProcessUniqueId(task_id);
+    // Ignore tasks that don't have a valid child process host ID like ARC
+    // processes. We report the browser process info here though.
+    if (child_process_host_id == content::ChildProcessHost::kInvalidUniqueID)
+      continue;
+
+    seen_processes.insert(proc_id);
+    api::processes::Process process;
+    FillProcessData(task_id, observed_task_manager(), true, &process);

[Devlin, 2016/03/03 23:12:43]

doc anonymous bool

[afakhry, 2016/03/08 01:37:29]

Done here and in all.

+
+    if (has_on_updated_with_memory_listeners) {
+      // Append the private memory usage to the process data.
+      const int64_t private_memory =
+          observed_task_manager()->GetPrivateMemoryUsage(task_id);
+      process.private_memory.reset(new double(static_cast<double>(
+          private_memory)));
     }
-  }
-
-  if (updated) {
+
+    // Store each process indexed by the string version of its ChildProcessHost
+    // ID.
+    processes_dictionary.Set(base::IntToString(child_process_host_id),
+                             process.ToValue());
+  }
+
+  // Done with data collection. Now dispatch the appropriate events according to
+  // the present listeners.
+  DCHECK(has_on_updated_listeners || has_on_updated_with_memory_listeners);
+  if (has_on_updated_listeners) {
     api::processes::OnUpdated::Processes processes;
     processes.additional_properties.MergeDictionary(&processes_dictionary);
     // NOTE: If there are listeners to the updates with memory as well,
     // listeners to onUpdated (without memory) will also get the memory info
     // of processes as an added bonus.
     DispatchEvent(events::PROCESSES_ON_UPDATED,
                   api::processes::OnUpdated::kEventName,
                   api::processes::OnUpdated::Create(processes));
   }
 
-  if (updated_memory) {
+  if (has_on_updated_with_memory_listeners) {
     api::processes::OnUpdatedWithMemory::Processes processes;
     processes.additional_properties.MergeDictionary(&processes_dictionary);
     DispatchEvent(events::PROCESSES_ON_UPDATED_WITH_MEMORY,
                   api::processes::OnUpdatedWithMemory::kEventName,
-                  api::processes::OnUpdatedWithMemory::Create(processes));}
-#endif  // defined(ENABLE_TASK_MANAGER)
+                  api::processes::OnUpdatedWithMemory::Create(processes));
+  }
 }
 
-void ProcessesEventRouter::OnItemsToBeRemoved(int start, int length) {
-#if defined(ENABLE_TASK_MANAGER)
-  DCHECK_EQ(length, 1);
-
-  if (!HasEventListeners(api::processes::OnExited::kEventName))
-    return;
-
-  // Process exit for renderer processes has the data about exit code and
-  // termination status, therefore we will rely on notifications and not on
-  // the Task Manager data. We do use the rest of this method for non-renderer
-  // processes.
-  if (model_->GetResourceType(start) == task_manager::Resource::RENDERER)
-    return;
-
-  DispatchEvent(events::PROCESSES_ON_EXITED,
-                api::processes::OnExited::kEventName,
-                api::processes::OnExited::Create(
-                    model_->GetUniqueChildProcessId(start),
-                    0 /* exit_type */,
-                    0 /* exit_code */));
-#endif  // defined(ENABLE_TASK_MANAGER)
-}
-
-void ProcessesEventRouter::ProcessHangEvent(content::RenderWidgetHost* widget) {
-#if defined(ENABLE_TASK_MANAGER)
+void ProcessesEventRouter::OnTaskUnresponsive(task_management::TaskId id) {
   if (!HasEventListeners(api::processes::OnUnresponsive::kEventName))
     return;
 
-  int count = model_->ResourceCount();
-  int id = widget->GetProcess()->GetID();
-
-  for (int i = 0; i < count; ++i) {
-    if (model_->IsResourceFirstInGroup(i)) {
-      if (id == model_->GetUniqueChildProcessId(i)) {
-        api::processes::Process process;
-        FillProcessData(id, model_, i, false /* include_optional */, &process);
-        DispatchEvent(events::PROCESSES_ON_UNRESPONSIVE,
-                      api::processes::OnUnresponsive::kEventName,
-                      api::processes::OnUnresponsive::Create(process));
-        return;
-      }
-    }
-  }
-#endif  // defined(ENABLE_TASK_MANAGER)
-}
-
-void ProcessesEventRouter::ProcessClosedEvent(
-    content::RenderProcessHost* rph,
-    content::RenderProcessHost::RendererClosedDetails* details) {
-#if defined(ENABLE_TASK_MANAGER)
-  if (!HasEventListeners(api::processes::OnExited::kEventName))
-    return;
-
-  DispatchEvent(events::PROCESSES_ON_EXITED,
-                api::processes::OnExited::kEventName,
-                api::processes::OnExited::Create(rph->GetID(),
-                                                 details->status,
-                                                 details->exit_code));
-#endif  // defined(ENABLE_TASK_MANAGER)
+  api::processes::Process process;
+  FillProcessData(id, observed_task_manager(), false, &process);
+  DispatchEvent(events::PROCESSES_ON_UNRESPONSIVE,
+                api::processes::OnUnresponsive::kEventName,
+                api::processes::OnUnresponsive::Create(process));
 }
 
 void ProcessesEventRouter::DispatchEvent(
     events::HistogramValue histogram_value,
     const std::string& event_name,
-    scoped_ptr<base::ListValue> event_args) {
+    scoped_ptr<base::ListValue> event_args) const {
   EventRouter* event_router = EventRouter::Get(browser_context_);
   if (event_router) {
     scoped_ptr<Event> event(
         new Event(histogram_value, event_name, std::move(event_args)));
     event_router->BroadcastEvent(std::move(event));
   }
 }
 
-bool ProcessesEventRouter::HasEventListeners(const std::string& event_name) {
+bool ProcessesEventRouter::HasEventListeners(
+    const std::string& event_name) const {
   EventRouter* event_router = EventRouter::Get(browser_context_);
   return event_router && event_router->HasEventListener(event_name);
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// ProcessesAPI:
+////////////////////////////////////////////////////////////////////////////////
+
 ProcessesAPI::ProcessesAPI(content::BrowserContext* context)
     : browser_context_(context) {
   EventRouter* event_router = EventRouter::Get(browser_context_);
   // Monitor when the following events are being listened to in order to know
   // when to start the task manager.
   event_router->RegisterObserver(this, api::processes::OnUpdated::kEventName);
   event_router->RegisterObserver(
       this, api::processes::OnUpdatedWithMemory::kEventName);
   event_router->RegisterObserver(this, api::processes::OnCreated::kEventName);
   event_router->RegisterObserver(this,
                                  api::processes::OnUnresponsive::kEventName);
   event_router->RegisterObserver(this, api::processes::OnExited::kEventName);
 }
 
 ProcessesAPI::~ProcessesAPI() {
+  // This object has already been unregistered as an observer in Shutdown().
 }
 
-void ProcessesAPI::Shutdown() {
-  EventRouter::Get(browser_context_)->UnregisterObserver(this);
-}
-
-static base::LazyInstance<BrowserContextKeyedAPIFactory<ProcessesAPI> >
-    g_factory = LAZY_INSTANCE_INITIALIZER;
-
 // static
 BrowserContextKeyedAPIFactory<ProcessesAPI>*
 ProcessesAPI::GetFactoryInstance() {
-  return g_factory.Pointer();
+  return g_processes_api_factory.Pointer();
 }
 
 // static
 ProcessesAPI* ProcessesAPI::Get(content::BrowserContext* context) {
   return BrowserContextKeyedAPIFactory<ProcessesAPI>::Get(context);
 }
 
+void ProcessesAPI::Shutdown() {
+  EventRouter::Get(browser_context_)->UnregisterObserver(this);
+}
+
+void ProcessesAPI::OnListenerAdded(const EventListenerInfo& details) {
+  // The ProcessesEventRouter will observe the TaskManager as long as there are
+  // listeners for the processes.onUpdated/.onUpdatedWithMemory/.onCreated ...
+  // etc. events.
+  processes_event_router()->ListenerAdded();
+}
+
+void ProcessesAPI::OnListenerRemoved(const EventListenerInfo& details) {
+  // If a processes.onUpdated/.onUpdatedWithMemory/.onCreated ... etc. event
+  // listener is removed (or a process with one exits), then we let the
+  // extension API know that it has one fewer listener.
+  processes_event_router()->ListenerRemoved();
+}
+
 ProcessesEventRouter* ProcessesAPI::processes_event_router() {
-  if (!processes_event_router_)
+  if (!processes_event_router_.get())
     processes_event_router_.reset(new ProcessesEventRouter(browser_context_));
   return processes_event_router_.get();
 }
 
-void ProcessesAPI::OnListenerAdded(const EventListenerInfo& details) {
-  // We lazily tell the TaskManager to start updating when listeners to the
-  // processes.onUpdated or processes.onUpdatedWithMemory events arrive.
-  processes_event_router()->ListenerAdded();
-}
-
-void ProcessesAPI::OnListenerRemoved(const EventListenerInfo& details) {
-  // If a processes.onUpdated or processes.onUpdatedWithMemory event listener
-  // is removed (or a process with one exits), then we let the extension API
-  // know that it has one fewer listener.
-  processes_event_router()->ListenerRemoved();
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 // ProcessesGetProcessIdForTabFunction:
 ////////////////////////////////////////////////////////////////////////////////
 
-ProcessesGetProcessIdForTabFunction::ProcessesGetProcessIdForTabFunction()
-    : tab_id_(-1) {
-}
-
 ExtensionFunction::ResponseAction ProcessesGetProcessIdForTabFunction::Run() {
-#if defined(ENABLE_TASK_MANAGER)
+  // For this function, the task manager doesn't even need to be running.
   scoped_ptr<api::processes::GetProcessIdForTab::Params> params(
-  api::processes::GetProcessIdForTab::Params::Create(*args_));
+      api::processes::GetProcessIdForTab::Params::Create(*args_));
   EXTENSION_FUNCTION_VALIDATE(params.get());
-  tab_id_ = params->tab_id;
-
-  if (tab_id_ < 0) {
-    return RespondNow(Error(errors::kInavlidArgument,
-                            base::IntToString(tab_id_)));
-  }
-
-  // Add a reference, which is balanced in GetProcessIdForTab to keep the object
-  // around and allow for the callback to be invoked.
-  AddRef();
-
-  // If the task manager is already listening, just post a task to execute
-  // which will invoke the callback once we have returned from this function.
-  // Otherwise, wait for the notification that the task manager is done with
-  // the data gathering.
-  if (ProcessesAPI::Get(Profile::FromBrowserContext(browser_context()))
-          ->processes_event_router()
-          ->is_task_manager_listening()) {
-    base::ThreadTaskRunnerHandle::Get()->PostTask(
-        FROM_HERE,
-        base::Bind(&ProcessesGetProcessIdForTabFunction::GetProcessIdForTab,
-                   this));
-  } else {
-    TaskManager::GetInstance()->model()->RegisterOnDataReadyCallback(
-        base::Bind(&ProcessesGetProcessIdForTabFunction::GetProcessIdForTab,
-                   this));
-
-    ProcessesAPI::Get(Profile::FromBrowserContext(browser_context()))
-        ->processes_event_router()
-        ->StartTaskManagerListening();
-  }
-
-  return RespondLater();
-#else
-  return RespondNow(Error(errors::kExtensionNotSupported));
-#endif  // defined(ENABLE_TASK_MANAGER)
-}
-
-void ProcessesGetProcessIdForTabFunction::GetProcessIdForTab() {
-  content::WebContents* contents = NULL;
+
+  const int tab_id = params->tab_id;
+  content::WebContents* contents = nullptr;
   int tab_index = -1;
   if (!ExtensionTabUtil::GetTabById(
-          tab_id_,
+          tab_id,
           Profile::FromBrowserContext(browser_context()),
           include_incognito(),
           nullptr,
           nullptr,
           &contents,
           &tab_index)) {
-    Respond(Error(tabs_constants::kTabNotFoundError,
-                  base::IntToString(tab_id_)));
-  } else {
-    int process_id = contents->GetRenderProcessHost()->GetID();
-    Respond(ArgumentList(
-        api::processes::GetProcessIdForTab::Results::Create(process_id)));
-  }
-
-  // Balance the AddRef in the Run.
-  Release();
-}
-
-////////////////////////////////////////////////////////////////////////////////
-// ProcessesTerminateFunction
-////////////////////////////////////////////////////////////////////////////////
-
-ProcessesTerminateFunction::ProcessesTerminateFunction() : process_id_(-1) {
-}
+    return RespondNow(Error(tabs_constants::kTabNotFoundError,
+                            base::IntToString(tab_id)));
+  }
+
+  const int process_id = contents->GetRenderProcessHost()->GetID();
+  return RespondNow(ArgumentList(
+      api::processes::GetProcessIdForTab::Results::Create(process_id)));
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// ProcessesTerminateFunction:
+////////////////////////////////////////////////////////////////////////////////
 
 ExtensionFunction::ResponseAction ProcessesTerminateFunction::Run() {
-#if defined(ENABLE_TASK_MANAGER)
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+  // For this function, the task manager doesn't even need to be running.
   scoped_ptr<api::processes::Terminate::Params> params(
       api::processes::Terminate::Params::Create(*args_));
   EXTENSION_FUNCTION_VALIDATE(params.get());
-  process_id_ = params->process_id;
-
-  // Add a reference, which is balanced in TerminateProcess to keep the object
-  // around and allow for the callback to be invoked.
-  AddRef();
-
-  // If the task manager is already listening, just post a task to execute
-  // which will invoke the callback once we have returned from this function.
-  // Otherwise, wait for the notification that the task manager is done with
-  // the data gathering.
-  if (ProcessesAPI::Get(Profile::FromBrowserContext(browser_context()))
-          ->processes_event_router()
-          ->is_task_manager_listening()) {
-    base::ThreadTaskRunnerHandle::Get()->PostTask(
-        FROM_HERE, base::Bind(&ProcessesTerminateFunction::TerminateProcess,
-                              this));
-  } else {
-    TaskManager::GetInstance()->model()->RegisterOnDataReadyCallback(
-        base::Bind(&ProcessesTerminateFunction::TerminateProcess, this));
-
-    ProcessesAPI::Get(Profile::FromBrowserContext(browser_context()))
-        ->processes_event_router()
-        ->StartTaskManagerListening();
-  }
-
+
+  child_process_host_id_ = params->process_id;
+  if (child_process_host_id_ < 0) {
+    return RespondNow(Error(errors::kInvalidArgument,
+                            base::IntToString(child_process_host_id_)));
+  } else if (child_process_host_id_ == 0) {
+    // Cannot kill the browser process.
+    return RespondNow(Error(errors::kNotAllowedToTerminate,
+                            base::IntToString(child_process_host_id_)));
+  }
+
+  content::BrowserThread::PostTaskAndReplyWithResult(
+      content::BrowserThread::IO,
+      FROM_HERE,
+      base::Bind(&ProcessesTerminateFunction::GetProcessHandleIO,
+                 this,
+                 child_process_host_id_),
+      base::Bind(&ProcessesTerminateFunction::OnProcessHandleUI, this));
+
+  // Promise to respond later.
   return RespondLater();
-#else
-  return RespondNow(Error(errors::kExtensionNotSupported));
-#endif  // defined(ENABLE_TASK_MANAGER)
-}
-
-void ProcessesTerminateFunction::TerminateProcess() {
-#if defined(ENABLE_TASK_MANAGER)
-  TaskManagerModel* model = TaskManager::GetInstance()->model();
-
-  bool found = false;
-  for (int i = 0, count = model->ResourceCount(); i < count; ++i) {
-    if (model->IsResourceFirstInGroup(i) &&
-        process_id_ == model->GetUniqueChildProcessId(i)) {
-      base::ProcessHandle process_handle = model->GetProcess(i);
-      if (process_handle == base::GetCurrentProcessHandle()) {
-        // Cannot kill the browser process.
-        // TODO(kalman): Are there other sensitive processes?
-        Respond(Error(errors::kNotAllowedToTerminate,
-                      base::IntToString(process_id_)));
-      } else {
-        base::Process process =
-            base::Process::DeprecatedGetProcessFromHandle(process_handle);
-        bool did_terminate =
-            process.Terminate(content::RESULT_CODE_KILLED, true);
-        if (did_terminate)
-          UMA_HISTOGRAM_COUNTS("ChildProcess.KilledByExtensionAPI", 1);
-
-        Respond(ArgumentList(
-            api::processes::Terminate::Results::Create(did_terminate)));
-      }
-      found = true;
-      break;
-    }
-  }
-
-  if (!found)
-    Respond(Error(errors::kProcessNotFound, base::IntToString(process_id_)));
-
-  // Balance the AddRef in the Run.
-  Release();
-#endif  // defined(ENABLE_TASK_MANAGER)
-}
-
-////////////////////////////////////////////////////////////////////////////////
-// ProcessesGetProcessInfoFunction
+}
+
+base::ProcessHandle ProcessesTerminateFunction::GetProcessHandleIO(
+    int child_process_host_id) const {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+
+  auto* host = content::BrowserChildProcessHost::FromID(child_process_host_id);
+  if (host)
+    return host->GetData().handle;
+
+  return base::kNullProcessHandle;
+}
+
+void ProcessesTerminateFunction::OnProcessHandleUI(base::ProcessHandle handle) {

[Devlin, 2016/03/03 23:12:43]

I don't know much about base::ProcessHandles and BrowserChildProcessHosts - is
it thread safe to pass the handle around like this?

[afakhry, 2016/03/08 01:37:29]

I'm not sure, but the task manager is already using this pattern and I'm not
aware of any problems.

+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+  if (handle == base::kNullProcessHandle) {
+    // If we didn't get anything from BrowserChildProcessHost, then it could be
+    // a renderer.
+    auto* render_process_host =
+        content::RenderProcessHost::FromID(child_process_host_id_);
+    if (render_process_host)

[Devlin, 2016/03/03 23:12:43]

Would it be cheaper to try this before we do the thread hop?

[afakhry, 2016/03/08 01:37:29]

Great idea! Done.

+      handle = render_process_host->GetHandle();
+  }
+
+  if (handle == base::kNullProcessHandle) {
+    Respond(Error(errors::kProcessNotFound,
+                  base::IntToString(child_process_host_id_)));
+    return;
+  }
+
+  if (handle == base::GetCurrentProcessHandle()) {
+    // Cannot kill the browser process.
+    Respond(Error(errors::kNotAllowedToTerminate,
+                  base::IntToString(child_process_host_id_)));
+    return;
+  }
+
+  base::Process process = base::Process::Open(base::GetProcId(handle));
+  const bool did_terminate =
+      process.Terminate(content::RESULT_CODE_KILLED, true);
+  if (did_terminate)
+    UMA_HISTOGRAM_COUNTS("ChildProcess.KilledByExtensionAPI", 1);
+
+  Respond(ArgumentList(
+      api::processes::Terminate::Results::Create(did_terminate)));
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// ProcessesGetProcessInfoFunction:
 ////////////////////////////////////////////////////////////////////////////////
 
 ProcessesGetProcessInfoFunction::ProcessesGetProcessInfoFunction()
-#if defined(ENABLE_TASK_MANAGER)
-  : memory_(false)
-#endif
-    {
+    : task_management::TaskManagerObserver(
+          base::TimeDelta::FromSeconds(1),
+          GetRefreshTypesFlagOnlyEssentialData()) {
 }
 
 ExtensionFunction::ResponseAction ProcessesGetProcessInfoFunction::Run() {
-#if defined(ENABLE_TASK_MANAGER)
   scoped_ptr<api::processes::GetProcessInfo::Params> params(
       api::processes::GetProcessInfo::Params::Create(*args_));
   EXTENSION_FUNCTION_VALIDATE(params.get());
   if (params->process_ids.as_integer)
-    process_ids_.push_back(*params->process_ids.as_integer);
+    process_host_ids_.push_back(*params->process_ids.as_integer);
   else
-    process_ids_.swap(*params->process_ids.as_integers);
-
-  memory_ = params->include_memory;
-
-  // Add a reference, which is balanced in GatherProcessInfo to keep the object
-  // around and allow for the callback to be invoked.
+    process_host_ids_.swap(*params->process_ids.as_integers);
+
+  include_memory_ = params->include_memory;
+  if (include_memory_)
+    AddRefreshType(task_management::REFRESH_TYPE_MEMORY);
+
+  // Keep this object alive until the first of either OnTasksRefreshed() or
+  // OnTasksRefreshedWithBackgroundCalculations() is received depending on
+  // |include_memory_|.
   AddRef();
 
-  // If the task manager is already listening, just post a task to execute
-  // which will invoke the callback once we have returned from this function.
-  // Otherwise, wait for the notification that the task manager is done with
-  // the data gathering.
-  if (ProcessesAPI::Get(Profile::FromBrowserContext(browser_context()))
-          ->processes_event_router()
-          ->is_task_manager_listening()) {
-    base::ThreadTaskRunnerHandle::Get()->PostTask(
-        FROM_HERE,
-        base::Bind(&ProcessesGetProcessInfoFunction::GatherProcessInfo, this));
-  } else {
-    TaskManager::GetInstance()->model()->RegisterOnDataReadyCallback(
-        base::Bind(&ProcessesGetProcessInfoFunction::GatherProcessInfo, this));
-
-    ProcessesAPI::Get(Profile::FromBrowserContext(browser_context()))
-        ->processes_event_router()
-        ->StartTaskManagerListening();
-  }
+  // The task manager needs to be enabled for this function.
+  // Start observing the task manager and wait for the next refresh event.
+  task_management::TaskManagerInterface::GetTaskManager()->AddObserver(this);
 
   return RespondLater();
-#else
-  return RespondNow(Error(errors::kExtensionNotSupported));
-#endif  // defined(ENABLE_TASK_MANAGER)
-}
-
-ProcessesGetProcessInfoFunction::~ProcessesGetProcessInfoFunction() {
-}
-
-void ProcessesGetProcessInfoFunction::GatherProcessInfo() {
-#if defined(ENABLE_TASK_MANAGER)
-  TaskManagerModel* model = TaskManager::GetInstance()->model();
-  api::processes::GetProcessInfo::Results::Processes processes;
-
+}
+
+void ProcessesGetProcessInfoFunction::OnTasksRefreshed(
+    const task_management::TaskIdList& task_ids) {
+  // Memory is background calculated and will be ready when
+  // OnTasksRefreshedWithBackgroundCalculations() is invoked.
+  if (include_memory_)
+    return;
+
+  GatherDataAndRespond(task_ids);
+}
+
+void
+ProcessesGetProcessInfoFunction::OnTasksRefreshedWithBackgroundCalculations(
+    const task_management::TaskIdList& task_ids) {
+  if (!include_memory_)
+    return;
+
+  GatherDataAndRespond(task_ids);
+}
+
+ProcessesGetProcessInfoFunction::~ProcessesGetProcessInfoFunction() {}
+
+void ProcessesGetProcessInfoFunction::GatherDataAndRespond(
+    const task_management::TaskIdList& task_ids) {
   // If there are no process IDs specified, it means we need to return all of
   // the ones we know of.
-  if (process_ids_.size() == 0) {
-    int resources = model->ResourceCount();
-    for (int i = 0; i < resources; ++i) {
-      if (model->IsResourceFirstInGroup(i)) {
-        int id = model->GetUniqueChildProcessId(i);
-        api::processes::Process process;
-        FillProcessData(id, model, i, false, &process);
-        if (memory_)
-          AddMemoryDetails(model, i, &process);
-        processes.additional_properties.Set(base::IntToString(id),
-                                            process.ToValue());
-      }
+  const bool specific_processes_requested = !process_host_ids_.empty();
+  std::set<base::ProcessId> seen_processes;
+  // Create the results object as defined in the generated API from process.idl
+  // and fill it with the processes info.
+  api::processes::GetProcessInfo::Results::Processes processes;
+  for (const auto& task_id : task_ids) {
+    const base::ProcessId proc_id =
+        observed_task_manager()->GetProcessId(task_id);
+    if (seen_processes.count(proc_id))
+      continue;
+
+    const int child_process_host_id =
+        observed_task_manager()->GetChildProcessUniqueId(task_id);
+    // Ignore tasks that don't have a valid child process host ID like ARC
+    // processes. We report the browser process info here though.
+    if (child_process_host_id == content::ChildProcessHost::kInvalidUniqueID)
+      continue;
+
+    if (specific_processes_requested) {
+      // Note: we can't use |!process_host_ids_.empty()| directly in the above
+      // condition as we will erase from |process_host_ids_| below.
+      auto itr = std::find(process_host_ids_.begin(),
+                           process_host_ids_.end(),
+                           child_process_host_id);
+      if (itr == process_host_ids_.end())
+        continue;
+
+      // If found, we remove it from |process_host_ids|, so that at the end if
+      // anything remains in |process_host_ids|, those were invalid arguments
+      // that will be reported on the console.
+      process_host_ids_.erase(itr);
     }
-  } else {
-    int resources = model->ResourceCount();
-    for (int i = 0; i < resources; ++i) {
-      if (model->IsResourceFirstInGroup(i)) {
-        int id = model->GetUniqueChildProcessId(i);
-        std::vector<int>::iterator proc_id = std::find(process_ids_.begin(),
-                                                       process_ids_.end(), id);
-        if (proc_id != process_ids_.end()) {
-          api::processes::Process process;
-          FillProcessData(id, model, i, false, &process);
-          if (memory_)
-            AddMemoryDetails(model, i, &process);
-          processes.additional_properties.Set(base::IntToString(id),
-                                              process.ToValue());
-
-          process_ids_.erase(proc_id);
-          if (process_ids_.size() == 0)
-            break;
-        }
-      }
+
+    seen_processes.insert(proc_id);
+
+    // We do not include the optional data in this function results.
+    api::processes::Process process;
+    FillProcessData(task_id, observed_task_manager(), false, &process);
+
+    if (include_memory_) {
+      // Append the private memory usage to the process data.
+      const int64_t private_memory =
+          observed_task_manager()->GetPrivateMemoryUsage(task_id);
+      process.private_memory.reset(new double(static_cast<double>(
+          private_memory)));
     }
-    // If not all processes were found, log them to the extension's console to
-    // help the developer, but don't fail the API call.
-    for (int pid : process_ids_) {
-      WriteToConsole(content::CONSOLE_MESSAGE_LEVEL_ERROR,
-                     ErrorUtils::FormatErrorMessage(errors::kProcessNotFound,
-                                                    base::IntToString(pid)));
-    }
+
+    // Store each process indexed by the string version of its
+    // ChildProcessHost ID.
+    processes.additional_properties.Set(
+        base::IntToString(child_process_host_id),
+        process.ToValue());
+  }
+
+  // Report the invalid host ids sent in the arguments.
+  for (const auto& host_id : process_host_ids_) {
+    WriteToConsole(content::CONSOLE_MESSAGE_LEVEL_ERROR,
+                   ErrorUtils::FormatErrorMessage(errors::kProcessNotFound,
+                                                  base::IntToString(host_id)));
   }
 
   // Send the response.
   Respond(ArgumentList(
       api::processes::GetProcessInfo::Results::Create(processes)));
 
-  // Balance the AddRef in the Run.
+  // Stop observing the task manager, and balance the AddRef() in Run().
+  task_management::TaskManagerInterface::GetTaskManager()->RemoveObserver(this);
   Release();
-#endif  // defined(ENABLE_TASK_MANAGER)
 }
 
 }  // namespace extensions