[tracing] Send unique tracing process id for cross-process memory dumps identification.

content/browser/tracing/tracing_controller_impl.cc

 // Copyright (c) 2013 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 "content/browser/tracing/tracing_controller_impl.h"
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/json/string_escape.h"
 #include "base/macros.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/trace_event/memory_allocator_dump_guid.h"
 #include "base/trace_event/trace_event.h"
 #include "content/browser/tracing/file_tracing_provider_impl.h"
 #include "content/browser/tracing/trace_message_filter.h"
 #include "content/browser/tracing/tracing_ui.h"
 #include "content/common/child_process_messages.h"
 #include "content/public/browser/browser_message_filter.h"
+#include "content/public/common/child_process_host.h"
 #include "content/public/common/content_switches.h"
 
 #if defined(OS_CHROMEOS)
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/debug_daemon_client.h"
 #endif
 
 #if defined(OS_WIN)
 #include "content/browser/tracing/etw_system_event_consumer_win.h"
 #endif
@@ skipping 101 matching lines @@
     chromeos::DBusThreadManager::Get()->GetDebugDaemonClient()->
       StartSystemTracing();
     is_system_tracing_ = true;
 #elif defined(OS_WIN)
     DCHECK(!is_system_tracing_);
     is_system_tracing_ =
         EtwSystemEventConsumer::GetInstance()->StartSystemTracing();
 #endif
   }
 
+  // Set the child process id for the browser process as invalid id.
+  base::trace_event::MemoryAllocatorDumpGuid::SetUniqueChildProcessId(
+      ChildProcessHost::kInvalidUniqueID);
 
   base::Closure on_enable_recording_done_callback =
       base::Bind(&TracingControllerImpl::OnEnableRecordingDone,
                  base::Unretained(this),
                  trace_config, callback);
   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
       base::Bind(&TracingControllerImpl::SetEnabledOnFileThread,
                  base::Unretained(this),
                  trace_config,
                  base::trace_event::TraceLog::RECORDING_MODE,
@@ skipping 711 matching lines @@
   is_monitoring_ = is_monitoring;
 #if !defined(OS_ANDROID)
   for (std::set<TracingUI*>::iterator it = tracing_uis_.begin();
        it != tracing_uis_.end(); it++) {
     (*it)->OnMonitoringStateChanged(is_monitoring);
   }
 #endif
 }
 
 }  // namespace content