Per-isolate v8::Locker and v8::Unlocker

src/isolate.h

Index: src/isolate.h
diff --git a/src/isolate.h b/src/isolate.h
index 01b721dc269048ae134148e21120532c1e7f8dcb..1639d62ccbf4db56b06dc800fd4a6a91f7273b05 100644
--- a/src/isolate.h
+++ b/src/isolate.h
@@ -220,6 +220,7 @@ class ThreadLocalTop BASE_EMBEDDED {
     ASSERT(try_catch_handler_address_ == NULL);
   }
 
+  Isolate* isolate_;
   // The context where the current execution method is created and for variable
   // lookups.
   Context* context_;
@@ -480,6 +481,10 @@ class Isolate {
   // Safe to call multiple times.
   static void EnsureDefaultIsolate();
 
+  // Find the PerThread for this particular (isolate, thread) combination
+  // If one does not yet exist, return null.
+  PerIsolateThreadData* FindPerThreadDataForThisThread();
+
   // Get the debugger from the default isolate. Preinitializes the
   // default isolate if needed.
   static Debugger* GetDefaultIsolateDebugger();
@@ -1063,6 +1068,10 @@ class Isolate {
   // If one does not yet exist, allocate a new one.
   PerIsolateThreadData* FindOrAllocatePerThreadDataForThisThread();
 
+  // Preinitialize this isolate for current thread. Thread-safe.
+  // Only called from v8::Locker implementation.
+  void EnsurePreinitializedForThisThread();
+
   // PreInits and returns a default isolate. Needed when a new thread tries
   // to create a Locker for the first time (the lock itself is in the isolate).
   static Isolate* GetDefaultIsolateForLocking();
@@ -1197,9 +1206,12 @@ class Isolate {
 
   friend class ExecutionAccess;
   friend class IsolateInitializer;
+  friend class ThreadManager;
+  friend class StackGuard;
   friend class ThreadId;
   friend class v8::Isolate;
   friend class v8::Locker;
+  friend class v8::Unlocker;
 
   DISALLOW_COPY_AND_ASSIGN(Isolate);
 };