[tracing] Add native allocation tracing mode.

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 53532b231242ff567e07486f680c1819cf6bb092..43b4fb8e017dbaa353aae959ddeabe2b7e597416 100644
--- a/base/trace_event/memory_dump_manager.cc
+++ b/base/trace_event/memory_dump_manager.cc
@@ -169,7 +169,30 @@ void MemoryDumpManager::EnableHeapProfilingIfNeeded() {
           switches::kEnableHeapProfiling))
     return;
 
-  AllocationContextTracker::SetCaptureEnabled(true);
+  std::string profiling_mode = CommandLine::ForCurrentProcess()
+      ->GetSwitchValueASCII(switches::kEnableHeapProfiling);
+  bool profiling_mode_parsed = false;
+  if (profiling_mode == "") {
+    AllocationContextTracker::SetCaptureMode(
+        AllocationContextTracker::CaptureMode::PSEUDO_STACK);
+    profiling_mode_parsed = true;
+  }
+#if ENABLE_NATIVE_ALLOCATION_TRACES
+  else if (profiling_mode == switches::kEnableHeapProfilingModeNative) {
+    AllocationContextTracker::SetCaptureMode(
+        AllocationContextTracker::CaptureMode::NATIVE_STACK);
+    profiling_mode_parsed = true;
+  }
+#endif
+  if (!profiling_mode_parsed) {
+    LOG(ERROR) << "Ignored unknown mode '" << profiling_mode << "' for "

[Primiano Tucci (use gerrit), 2016/04/19 20:15:19]

there is a discussion on chromium-dev about LOG. TL;DR we shouldn't add any log
statement. LOG(ERROR) is too easy to overlook. Let' make it hard crash.
Let's make this as follows:
First of all get rid of profiling_mode_parsed, doesn't seem really useful.
if (profiling_mode == "") {
...
} else if (profiling_mode == kNative) {
 #if ENABLE_NATIVE
   ...
 #else
   CHECK(false) << "Need either a debug or profiling=1 build to use bla=native"
 #
} else {
 CHECK(false) << "Unsupported mode ..."
}

[Dmitry Skiba, 2016/04/20 19:19:25]

Done.

+               << switches::kEnableHeapProfiling << " flag.";
+
+    // Enable pseudo stacks
+    AllocationContextTracker::SetCaptureMode(
+        AllocationContextTracker::CaptureMode::PSEUDO_STACK);
+  }
+
   for (auto mdp : dump_providers_)
     mdp->dump_provider->OnHeapProfilingEnabled(true);
   heap_profiling_enabled_ = true;