[tracing] Dump child processes' memory metrics in browser

base/trace_event/memory_dump_manager.cc

Index: base/trace_event/memory_dump_manager.cc
diff --git a/base/trace_event/memory_dump_manager.cc b/base/trace_event/memory_dump_manager.cc
index f3f74cdd647192c63f417250d5947a1ea86f26e8..4bd0eb23f69f13e0aa2d3e26309a1c4482dc3dd0 100644
--- a/base/trace_event/memory_dump_manager.cc
+++ b/base/trace_event/memory_dump_manager.cc
@@ -19,13 +19,8 @@
 #include "base/trace_event/trace_event_argument.h"
 #include "build/build_config.h"
 
-#if !defined(OS_NACL)
-#include "base/trace_event/process_memory_totals_dump_provider.h"
-#endif
-
 #if defined(OS_LINUX) || defined(OS_ANDROID)
 #include "base/trace_event/malloc_dump_provider.h"
-#include "base/trace_event/process_memory_maps_dump_provider.h"
 #endif
 
 #if defined(OS_ANDROID)
@@ -150,23 +145,25 @@ void MemoryDumpManager::Initialize(MemoryDumpManagerDelegate* delegate,
   }
 
 // Enable the core dump providers.
-#if !defined(OS_NACL)
-  RegisterDumpProvider(ProcessMemoryTotalsDumpProvider::GetInstance(),
-                       "ProcessMemoryTotals", nullptr);
-#endif
+#if defined(OS_ANDROID)
+  const ProcessHandle current_process = GetCurrentProcessHandle();
+  scoped_ptr<ProcessMemoryTotalsDumpProvider> totals_provider(
+      ProcessMemoryTotalsDumpProvider::CreateForProcess(current_process));
+  RegisterDumpProvider(totals_provider.get(), "ProcessMemoryTotals", nullptr);
+  process_totals_providers_map_.insert(current_process, totals_provider.Pass());
 
-#if defined(OS_LINUX) || defined(OS_ANDROID)
-  RegisterDumpProvider(ProcessMemoryMapsDumpProvider::GetInstance(),
-                       "ProcessMemoryMaps", nullptr);
-  RegisterDumpProvider(MallocDumpProvider::GetInstance(), "Malloc", nullptr);
-#endif
+  scoped_ptr<ProcessMemoryMapsDumpProvider> mmaps_provider(
+      ProcessMemoryMapsDumpProvider::CreateForProcess(current_process));
+  RegisterDumpProvider(mmaps_provider.get(), "ProcessMemoryMaps", nullptr);
+  process_mmaps_providers_map_.insert(current_process, mmaps_provider.Pass());
 
-#if defined(OS_ANDROID)
   RegisterDumpProvider(JavaHeapDumpProvider::GetInstance(), "JavaHeap",
                        nullptr);
-#endif
+#endif  // defined(OS_ANDROID)
 
-#if defined(OS_WIN)
+#if defined(OS_LINUX) || defined(OS_ANDROID)
+  RegisterDumpProvider(MallocDumpProvider::GetInstance(), "Malloc", nullptr);
+#elif defined(OS_WIN)
   RegisterDumpProvider(WinHeapDumpProvider::GetInstance(), "WinHeap", nullptr);
 #endif
 
@@ -602,6 +599,42 @@ uint64_t MemoryDumpManager::GetTracingProcessId() const {
   return delegate_->GetTracingProcessId();
 }
 
+void MemoryDumpManager::RegisterProcessMetricsProvidersFor(
+    ProcessHandle process) {
+#if defined(OS_LINUX)
+  scoped_ptr<ProcessMemoryTotalsDumpProvider> totals_provider(
+      ProcessMemoryTotalsDumpProvider::CreateForProcess(process));
+  MemoryDumpProvider::Options totals_options = {process};
+  RegisterDumpProvider(totals_provider.get(), "ProcessMemoryTotals", nullptr,
+                       totals_options);
+  process_totals_providers_map_.insert(process, totals_provider.Pass());
+
+  scoped_ptr<ProcessMemoryMapsDumpProvider> mmaps_provider(
+      ProcessMemoryMapsDumpProvider::CreateForProcess(process));
+  MemoryDumpProvider::Options mmaps_options = {process};
+  RegisterDumpProvider(mmaps_provider.get(), "ProcessMemoryMaps", nullptr,
+                       mmaps_options);
+  process_mmaps_providers_map_.insert(process, mmaps_provider.Pass());
+#endif  // defined(OS_LINUX)
+}
+
+void MemoryDumpManager::UnregisterProcessMetricsProvidersFor(
+    ProcessHandle process) {
+#if defined(OS_LINUX)
+  ProcessTotalsDumpProvidersMap::const_iterator totals_it =
+      process_totals_providers_map_.find(process);
+  DCHECK(totals_it != process_totals_providers_map_.end());
+  UnregisterDumpProvider(totals_it->second);
+  process_totals_providers_map_.erase(totals_it);
+
+  ProcessMapsDumpProvidersMap::const_iterator mmaps_it =
+      process_mmaps_providers_map_.find(process);
+  DCHECK(mmaps_it != process_mmaps_providers_map_.begin());
+  UnregisterDumpProvider(mmaps_it->second);
+  process_mmaps_providers_map_.erase(mmaps_it);
+#endif  // defined(OS_LINUX)
+}
+
 MemoryDumpManager::MemoryDumpProviderInfo::MemoryDumpProviderInfo(
     MemoryDumpProvider* dump_provider,
     const char* name,