[tracing] Send smaps file desciptor to child process for tracing

components/tracing/child_memory_dump_manager_delegate_impl.cc

 // Copyright 2015 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 "components/tracing/child_memory_dump_manager_delegate_impl.h"
 
 #include "base/single_thread_task_runner.h"
+#include "base/trace_event/process_memory_maps_dump_provider.h"
+#include "base/trace_event/process_memory_totals_dump_provider.h"
 #include "components/tracing/child_trace_message_filter.h"
 
 namespace tracing {
 
 namespace {
 void AbortDumpRequest(const base::trace_event::MemoryDumpRequestArgs& args,
                       const base::trace_event::MemoryDumpCallback& callback) {
   if (!callback.is_null())
     callback.Run(args.dump_guid, false /* success */);
 }
@@ skipping 65 matching lines @@
 
   // The ChildTraceMessageFilter could have been destroyed while hopping on the
   // right thread. If this is the case, bail out.
   if (!ctmf_)
     return AbortDumpRequest(args, callback);
 
   // Send the request up to the browser process' MessageDumpmanager.
   ctmf_->SendGlobalMemoryDumpRequest(args, callback);
 }
 
+void ChildMemoryDumpManagerDelegateImpl::SetMemoryTracingInfo(
+    const TracingMsg_MemoryTracingInfo& memory_tracing_info) {
+  // Checks if id is not reset to different one.
+  DCHECK_IMPLIES(
+      tracing_process_id_ !=
+          base::trace_event::MemoryDumpManager::kInvalidTracingProcessId,
+      memory_tracing_info.tracing_process_id == tracing_process_id_);
+  tracing_process_id_ = memory_tracing_info.tracing_process_id;
+
+#if defined(OS_LINUX)
+  base::trace_event::ProcessMemoryMapsDumpProvider::GetInstance()
+      ->set_smaps_file(fdopen(IPC::PlatformFileForTransitToPlatformFile(
+                                  memory_tracing_info.smaps_fd),
+                              "r"));
+  base::trace_event::ProcessMemoryTotalsDumpProvider::GetInstance()
+      ->set_proc_status_fd(IPC::PlatformFileForTransitToPlatformFile(
+          memory_tracing_info.status_fd));
+#endif
+}
+
+void ChildMemoryDumpManagerDelegateImpl::ResetMemoryTracingInfo() {
+#if defined(OS_LINUX)
+  tracing_process_id_ =
+      base::trace_event::MemoryDumpManager::kInvalidTracingProcessId;
+  base::trace_event::ProcessMemoryMapsDumpProvider::GetInstance()
+      ->set_smaps_file(nullptr);
+  base::trace_event::ProcessMemoryTotalsDumpProvider::GetInstance()
+      ->reset_proc_status_fd();
+#endif
+}
+
 uint64 ChildMemoryDumpManagerDelegateImpl::GetTracingProcessId() const {
   return tracing_process_id_;
 }
 
 }  // namespace tracing