[tracing] Dump child processes' memory metrics in browser

base/trace_event/memory_dump_manager.h

Index: base/trace_event/memory_dump_manager.h
diff --git a/base/trace_event/memory_dump_manager.h b/base/trace_event/memory_dump_manager.h
index 662e0cf59120927ec272552cf265fba8cdac6a4e..d1af9f3509741088a9970ea345e8baa1e88f3e93 100644
--- a/base/trace_event/memory_dump_manager.h
+++ b/base/trace_event/memory_dump_manager.h
@@ -16,6 +16,8 @@
 #include "base/timer/timer.h"
 #include "base/trace_event/memory_dump_request_args.h"
 #include "base/trace_event/process_memory_dump.h"
+#include "base/trace_event/process_memory_maps_dump_provider.h"
+#include "base/trace_event/process_memory_totals_dump_provider.h"
 #include "base/trace_event/trace_event.h"
 
 namespace base {
@@ -97,6 +99,13 @@ class BASE_EXPORT MemoryDumpManager : public TraceLog::EnabledStateObserver {
   void OnTraceLogEnabled() override;
   void OnTraceLogDisabled() override;
 
+  // Registers and unregisters the process metrics dump providers for the
+  // |process|. Some processes cannot access metrics due to sandbox. To
+  // workaround the issue the coordinator process dumps statistics about the

[Primiano Tucci (use gerrit), 2015/11/03 15:14:08]

the manager should not need to know about all this.
Why do you want to keep track of them here?

+  // associated processes.
+  void RegisterProcessMetricsProvidersFor(ProcessHandle process);
+  void UnregisterProcessMetricsProvidersFor(ProcessHandle process);
+
   // Returns the MemoryDumpSessionState object, which is shared by all the
   // ProcessMemoryDump and MemoryAllocatorDump instances through all the tracing
   // session lifetime.
@@ -129,6 +138,11 @@ class BASE_EXPORT MemoryDumpManager : public TraceLog::EnabledStateObserver {
   friend class MemoryDumpManagerDelegate;
   friend class MemoryDumpManagerTest;
 
+  using ProcessTotalsDumpProvidersMap =
+      ScopedPtrMap<ProcessHandle, scoped_ptr<ProcessMemoryTotalsDumpProvider>>;
+  using ProcessMapsDumpProvidersMap =
+      ScopedPtrMap<ProcessHandle, scoped_ptr<ProcessMemoryMapsDumpProvider>>;
+
   // Descriptor struct used to hold information about registered MDPs. It is
   // deliberately copyable, in order to allow it to be used as std::set value.
   struct MemoryDumpProviderInfo {
@@ -240,6 +254,11 @@ class BASE_EXPORT MemoryDumpManager : public TraceLog::EnabledStateObserver {
   // affinity (MDPs belonging to the same thread are adjacent).
   MemoryDumpProviderInfoSet dump_providers_;
 
+  // MemoryDumpManager owns the memory maps and totals providers for all the
+  // associated processes.
+  ProcessTotalsDumpProvidersMap process_totals_providers_map_;
+  ProcessMapsDumpProvidersMap process_mmaps_providers_map_;
+
   // Shared among all the PMDs to keep state scoped to the tracing session.
   scoped_refptr<MemoryDumpSessionState> session_state_;