Introduce v8::Exception::GetMessage to find location of an error object.

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index e783727c2db5ad7310136342d1aa9a55cb8f8dc1..e72c8418b465d7d9d76afe06e093bbc293562c0c 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -4164,7 +4164,11 @@ class V8_EXPORT Exception {
   static Local<Value> TypeError(Handle<String> message);
   static Local<Value> Error(Handle<String> message);
 
-  static Local<StackTrace> GetStackTrace(Handle<Value> exception);
+  static Local<Message> GetMessage(Handle<Value> exception);
+
+  V8_DEPRECATED(
+      "Use GetMessage()->GetStackTrace()",
+      static Local<StackTrace> GetStackTrace(Handle<Value> exception));
 };
 
 
@@ -4224,7 +4228,11 @@ class PromiseRejectMessage {
   V8_INLINE Handle<Promise> GetPromise() const { return promise_; }
   V8_INLINE PromiseRejectEvent GetEvent() const { return event_; }
   V8_INLINE Handle<Value> GetValue() const { return value_; }
-  V8_INLINE Handle<StackTrace> GetStackTrace() const { return stack_trace_; }
+
+  V8_DEPRECATED("Use v8::Exception::GetMessage(GetValue())->GetStackTrace()",
+                V8_INLINE Handle<StackTrace> GetStackTrace() const) {
+    return stack_trace_;
+  }
 
  private:
   Handle<Promise> promise_;