[tracing] Dump child processes' memory metrics in browser

content/browser/tracing/tracing_controller_impl.cc

Index: content/browser/tracing/tracing_controller_impl.cc
diff --git a/content/browser/tracing/tracing_controller_impl.cc b/content/browser/tracing/tracing_controller_impl.cc
index 07347573a181dde527af44a1ee01ea2e6dd46e51..7fb1112131a0325367947e1d0f0c9bf323ec8518 100644
--- a/content/browser/tracing/tracing_controller_impl.cc
+++ b/content/browser/tracing/tracing_controller_impl.cc
@@ -9,6 +9,7 @@
 #include "base/macros.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/trace_event/trace_event.h"
+#include "components/tracing/process_metrics_memory_dump_manager.h"
 #include "content/browser/tracing/file_tracing_provider_impl.h"
 #include "content/browser/tracing/power_tracing_agent.h"
 #include "content/browser/tracing/trace_message_filter.h"
@@ -489,6 +490,9 @@ void TracingControllerImpl::AddTraceMessageFilter(
     return;
   }
 
+  tracing::ProcessMetricsMemoryDumpManager::GetInstance()->RegisterForProcess(
+      trace_message_filter->peer_pid());

[Primiano Tucci (use gerrit), 2015/11/17 10:44:13]

Shouldn't this be >PeerHandle() ?

[ssid, 2015/11/17 13:55:06]

Done.

+
   trace_message_filters_.insert(trace_message_filter);
   if (can_cancel_watch_event()) {
     trace_message_filter->SendSetWatchEvent(watch_category_name_,
@@ -517,6 +521,9 @@ void TracingControllerImpl::RemoveTraceMessageFilter(
     return;
   }
 
+  tracing::ProcessMetricsMemoryDumpManager::GetInstance()->UnregisterForProcess(
+      trace_message_filter->peer_pid());

[Primiano Tucci (use gerrit), 2015/11/17 10:44:12]

ditto

[ssid, 2015/11/17 13:55:06]

Done.

+
   // If a filter is removed while a response from that filter is pending then
   // simulate the response. Otherwise the response count will be wrong and the
   // completion callback will never be executed.