Reporting top cpu and memory consumers via rappor on chromeos

chrome/browser/task_management/sampling/task_group_sampler.cc

Index: chrome/browser/task_management/sampling/task_group_sampler.cc
diff --git a/chrome/browser/task_management/sampling/task_group_sampler.cc b/chrome/browser/task_management/sampling/task_group_sampler.cc
index e8999b3e2dcc6af350f320fd06f7fed86819ff08..8f7ddef73e517c93979223da8eac8b2de875cfbc 100644
--- a/chrome/browser/task_management/sampling/task_group_sampler.cc
+++ b/chrome/browser/task_management/sampling/task_group_sampler.cc
@@ -31,16 +31,20 @@ inline bool IsResourceRefreshEnabled(RefreshType refresh_type,
 }  // namespace
 
 TaskGroupSampler::TaskGroupSampler(
+    base::ProcessId proc_id,
     base::ProcessHandle proc_handle,
     const scoped_refptr<base::SequencedTaskRunner>& blocking_pool_runner,
     const OnCpuRefreshCallback& on_cpu_refresh,
     const OnMemoryRefreshCallback& on_memory_refresh,
-    const OnIdleWakeupsCallback& on_idle_wakeups)
+    const OnIdleWakeupsCallback& on_idle_wakeups,
+    const OnProcessPriorityCallback& on_process_priority)
     : process_metrics_(CreateProcessMetrics(proc_handle)),
       blocking_pool_runner_(blocking_pool_runner),
+      process_(base::Process::Open(proc_id)),

[ncarter (slow), 2015/11/20 18:44:45]

If we're doing base::Process::Open here, that gives us our own durable handle to
the pid, so we can pass that to process_metrics_. It's always better to use a
handle that you own, because using a handle that's been closed can result in a
crash.

I suggest .Pass()-ing a base::Process into the TaskGroupSampler ctor (replacing
both proc_id and proc_handle). Have the calling function do the Open call. 

[afakhry, 2015/11/21 01:32:58]

Thanks for this suggestion. It matches our decision to rely on the process id in
all the new task manager code. The only thing that still used a process handle
is the ProcessMetrics.

Done. Please take a look.

       on_cpu_refresh_callback_(on_cpu_refresh),
       on_memory_refresh_callback_(on_memory_refresh),
-      on_idle_wakeups_callback_(on_idle_wakeups) {
+      on_idle_wakeups_callback_(on_idle_wakeups),
+      on_process_priority_callback_(on_process_priority) {
   DCHECK(blocking_pool_runner.get());
 
   // This object will be created on the UI thread, however the sequenced checker
@@ -78,6 +82,14 @@ void TaskGroupSampler::Refresh(int64 refresh_flags) {
         on_idle_wakeups_callback_);
   }
 #endif  // defined(OS_MACOSX) || defined(OS_LINUX)
+
+  if (IsResourceRefreshEnabled(REFRESH_TYPE_PRIORITY, refresh_flags)) {
+    base::PostTaskAndReplyWithResult(
+        blocking_pool_runner_.get(),
+        FROM_HERE,
+        base::Bind(&TaskGroupSampler::RefreshProcessPriority, this),
+        on_process_priority_callback_);
+  }
 }
 
 TaskGroupSampler::~TaskGroupSampler() {
@@ -126,4 +138,10 @@ int TaskGroupSampler::RefreshIdleWakeupsPerSecond() {
   return process_metrics_->GetIdleWakeupsPerSecond();
 }
 
+bool TaskGroupSampler::RefreshProcessPriority() {
+  DCHECK(worker_pool_sequenced_checker_.CalledOnValidSequencedThread());
+
+  return process_.IsProcessBackgrounded();
+}
+
 }  // namespace task_management