Merge r7635 "Initialize ThreadLocalTop" to trunk.

src/isolate.h

Index: src/isolate.h
===================================================================
--- src/isolate.h	(revision 7635)
+++ src/isolate.h	(working copy)
@@ -185,6 +185,10 @@
 
 class ThreadLocalTop BASE_EMBEDDED {
  public:
+  // Does early low-level initialization that does not depend on the
+  // isolate being present.
+  ThreadLocalTop();
+
   // Initialize the thread data.
   void Initialize();
 
@@ -264,6 +268,8 @@
   v8::FailedAccessCheckCallback failed_access_check_callback_;
 
  private:
+  void InitializeInternal();
+
   Address try_catch_handler_address_;
 };