Separate output files for --trace-hydrogen.

src/isolate.h

Index: src/isolate.h
diff --git a/src/isolate.h b/src/isolate.h
index 3ab2b6a857a535b6093ba73f8768c6cc354f0f5c..73ec097ac86b61db38fdda960e7f366012db5fba 100644
--- a/src/isolate.h
+++ b/src/isolate.h
@@ -68,6 +68,7 @@ class Factory;
 class FunctionInfoListener;
 class HandleScopeImplementer;
 class HeapProfiler;
+class HTracer;
 class InlineRuntimeFunctionsTable;
 class NoAllocationStringAllocator;
 class InnerPointerToCodeCache;
@@ -371,6 +372,7 @@ typedef List<HeapObject*, PreallocatedStorageAllocationPolicy> DebugObjectCache;
   V(CpuProfiler*, cpu_profiler, NULL)                                          \
   V(HeapProfiler*, heap_profiler, NULL)                                        \
   V(bool, observer_delivery_pending, false)                                    \
+  V(HTracer*, htracer, NULL)                                                   \
   ISOLATE_DEBUGGER_INIT_LIST(V)
 
 class Isolate {
@@ -1099,9 +1101,13 @@ class Isolate {
     return sweeper_thread_;
   }
 
+  HTracer* GetHTracer();
+
  private:
   Isolate();
 
+  int id() const { return static_cast<int>(id_); }
+
   friend struct GlobalState;
   friend struct InitializeGlobalState;
 
@@ -1169,6 +1175,9 @@ class Isolate {
   static Isolate* default_isolate_;
   static ThreadDataTable* thread_data_table_;
 
+  // A global counter for all generated Isolates, might overflow.
+  static Atomic32 isolate_counter_;
+
   void Deinit();
 
   static void SetIsolateThreadLocals(Isolate* isolate,
@@ -1213,6 +1222,7 @@ class Isolate {
   // the Error object.
   bool IsErrorObject(Handle<Object> obj);
 
+  Atomic32 id_;
   EntryStackItem* entry_stack_;
   int stack_trace_nesting_level_;
   StringStream* incomplete_message_;