[tracing] Add native allocation tracing mode.

base/trace_event/memory_dump_manager.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 "base/trace_event/memory_dump_manager.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/atomic_sequence_num.h"
@@ skipping 152 matching lines @@
 
 void MemoryDumpManager::EnableHeapProfilingIfNeeded() {
   if (heap_profiling_enabled_)
     return;
 
   if (!CommandLine::InitializedForCurrentProcess() ||
       !CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnableHeapProfiling))
     return;
 
-  AllocationContextTracker::SetCaptureEnabled(true);
+  std::string profiling_mode = CommandLine::ForCurrentProcess()
+      ->GetSwitchValueASCII(switches::kEnableHeapProfiling);
+  if (profiling_mode == "") {
+    AllocationContextTracker::SetCaptureMode(
+        AllocationContextTracker::CaptureMode::PSEUDO_STACK);
+  }
+  else if (profiling_mode == switches::kEnableHeapProfilingModeNative) {
+#if ENABLE_NATIVE_ALLOCATION_TRACES
+    AllocationContextTracker::SetCaptureMode(
+        AllocationContextTracker::CaptureMode::NATIVE_STACK);
+#else
+    CHECK(false) << "'" << profiling_mode << "' mode for "
+                 << switches::kEnableHeapProfiling << " flag is not supported "
+                 << "for this platform / build type.";
+#endif
+  } else {
+    CHECK(false) << "Invalid mode '" << profiling_mode << "' for "
+               << switches::kEnableHeapProfiling << " flag.";
+  }
+
   for (auto mdp : dump_providers_)
     mdp->dump_provider->OnHeapProfilingEnabled(true);
   heap_profiling_enabled_ = true;
 }
 
 void MemoryDumpManager::Initialize(MemoryDumpManagerDelegate* delegate,
                                    bool is_coordinator) {
   {
     AutoLock lock(lock_);
     DCHECK(delegate);
@@ skipping 571 matching lines @@
   if (iter == process_dumps.end()) {
     std::unique_ptr<ProcessMemoryDump> new_pmd(
         new ProcessMemoryDump(session_state));
     iter = process_dumps.insert(std::make_pair(pid, std::move(new_pmd))).first;
   }
   return iter->second.get();
 }
 
 }  // namespace trace_event
 }  // namespace base