Support parallel captures from the StackSamplingProfiler.

base/profiler/native_stack_sampler.h

Index: base/profiler/native_stack_sampler.h
diff --git a/base/profiler/native_stack_sampler.h b/base/profiler/native_stack_sampler.h
index 8d7e441b69306b072ed67321a531ac76aee4e28c..b958894dbe95e2986a1f456046b5ba45b4ec27a8 100644
--- a/base/profiler/native_stack_sampler.h
+++ b/base/profiler/native_stack_sampler.h
@@ -21,6 +21,17 @@ class NativeStackSamplerTestDelegate;
 // given thread.
 class NativeStackSampler {
  public:
+  // The thread state as determined by the sampler during it's last attempt.

[Mike Wittman, 2017/02/13 22:35:57]

All changes in this file and native_stack_sampler_win.cc can be removed since
they're not adding any functionality to the existing implementation.

[bcwhite, 2017/02/14 14:33:01]

Done.

+  enum ThreadState {
+    THREAD_UNCHECKED,
+    THREAD_RUNNING,
+    THREAD_EXITED,
+    THREAD_UNSUSPENDABLE,
+    THREAD_NO_INFO,
+    THREAD_STACK_TOO_BIG,
+    THREAD_INACCESSIBLE,
+  };
+
   // The callback type used to add annotations to a sample during collection.
   // This is passed to the native sampler to be applied at the most appropriate
   // time. It is a simple function-pointer because the generated code must be
@@ -54,10 +65,17 @@ class NativeStackSampler {
   // profile.
   virtual void ProfileRecordingStopped() = 0;
 
+  // Gets the last-known thread state.
+  ThreadState thread_state() { return thread_state_; }
+
  protected:
   NativeStackSampler();
 
+  void set_thread_state(ThreadState state) { thread_state_ = state; }
+
  private:
+  ThreadState thread_state_ = THREAD_UNCHECKED;
+
   DISALLOW_COPY_AND_ASSIGN(NativeStackSampler);
 };
 
@@ -69,7 +87,10 @@ class BASE_EXPORT NativeStackSamplerTestDelegate {
 
   // Called after copying the stack and resuming the target thread, but prior to
   // walking the stack. Invoked on the SamplingThread.
-  virtual void OnPreStackWalk() = 0;
+  virtual void OnPreStackWalk(){};
+
+  // Called after the sampling is complete.
+  virtual void OnPostRecordSample(NativeStackSampler::ThreadState state){};
 
  protected:
   NativeStackSamplerTestDelegate();