Initial implementation of GetStackSample sampling profiler API.

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index ec1941e6fd86eec42707e4d41011112961fe2109..e546cb3e40b5558843ef8a613117852b9ee84832 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -1415,6 +1415,14 @@ class V8_EXPORT StackFrame {
 };
 
 
+struct RegisterState {
+  RegisterState() : pc(NULL), sp(NULL), fp(NULL) {}
+  void* pc;  // Instruction pointer.
+  void* sp;  // Stack pointer.
+  void* fp;  // Frame pointer.
+};
+
+
 /**
  * A JSON Parser.
  */
@@ -4548,6 +4556,19 @@ class V8_EXPORT Isolate {
   void GetHeapStatistics(HeapStatistics* heap_statistics);
 
   /**
+   * Get a call stack sample from the isolate.
+   * \param state Execution state.
+   * \param frames Caller allocated buffer to store stack frames.
+   * \param frames_limit Maximum number of frames to capture. The buffer must
+   *                     be large enough to hold the number of frames.
+   * \return Actual number of captured frames.
+   * \note GetStackSample should only be called when the JS thread is paused or
+   *       interrupted. Otherwise the behavior is undefined.
+   */
+  size_t GetStackSample(const RegisterState& state, void** frames,
+                        size_t frames_limit);
+
+  /**
    * Adjusts the amount of registered external memory. Used to give V8 an
    * indication of the amount of externally allocated memory that is kept alive
    * by JavaScript objects. V8 uses this to decide when to perform global