Add a new API V8::SetJitCodeEventHandler to push code name and location to users such as profilers.

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index 5c2c8b6671827f56ddddb6ef4a71182b6d54c164..44a580ad24e66d31cab5cc7d539bac484e1d31ec 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -2944,6 +2944,40 @@ typedef void (*FunctionEntryHook)(uintptr_t function,
 
 
 /**
+ * A JIT code event is issued each time code is added, moved or removed.
+ *
+ * \note removal events are not currently issued.
+ */
+struct JitCodeEvent {
+  enum EventType {
+    CODE_ADDED,
+    CODE_MOVED,
+    CODE_REMOVED
+  };
+
+  EventType type;
+  // Start of the instructions.
+  void* code_start;
+  // Size of the instructions.
+  size_t code_len;
+  union {
+    // Name of the object associated with the code. Only valid for CODE_ADDED.
+    const char* name;
+    // New location of instructions. Only valid for CODE_MOVED.
+    void* new_code_start;
+  };
+};
+
+
+/**
+ * Callback function passed to SetJitCodeEventHandler.
+ *
+ * \param event code add, move or removal event.
+ */
+typedef void (*JitCodeEventHandler)(const JitCodeEvent* event);
+
+
+/**
  * Interface for iterating though all external resources in the heap.
  */
 class V8EXPORT ExternalResourceVisitor {  // NOLINT
@@ -3218,6 +3252,15 @@ class V8EXPORT V8 {
   static bool SetFunctionEntryHook(FunctionEntryHook entry_hook);
 
   /**
+   * Allows the host application to provide the address of a function that is
+   * notified each time code is added, moved or removed.
+   *
+   * \param event_handler the JIT code event handler, which will be invoked
+   *     each time code is added, moved or removed.
+   */
+  static void SetJitCodeEventHandler(JitCodeEventHandler event_handler);
+
+  /**
    * 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