Make assertion scopes thread safe.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 54a522506287259d83a7684002e5ad1fac33fc07..ca92adee306d395aae16c8f2974a4d1570ba1c37 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -513,7 +513,7 @@ class ReachabilityAnalyzer BASE_EMBEDDED {
 
 void HGraph::Verify(bool do_full_verify) const {
   Heap::RelocationLock(isolate()->heap());
-  ALLOW_HANDLE_DEREF(isolate(), "debug mode verification");
+  AllowDeferredHandleDereference allow_deferred_deref;
   for (int i = 0; i < blocks_.length(); i++) {
     HBasicBlock* block = blocks_.at(i);
 
@@ -2040,7 +2040,7 @@ HBasicBlock* HGraph::CreateBasicBlock() {
 
 
 void HGraph::FinalizeUniqueValueIds() {
-  AssertNoAllocation no_gc;
+  DisallowHeapAllocation no_gc;
   ASSERT(!isolate()->optimizing_compiler_thread()->IsOptimizerThread());
   for (int i = 0; i < blocks()->length(); ++i) {
     for (HInstruction* instr = blocks()->at(i)->first();
@@ -4537,7 +4537,7 @@ void HGraph::MarkLive(HValue* ref, HValue* instr, ZoneList<HValue*>* worklist) {
     if (FLAG_trace_dead_code_elimination) {
       HeapStringAllocator allocator;
       StringStream stream(&allocator);
-      ALLOW_HANDLE_DEREF(isolate(), "debug mode printing");
+      AllowDeferredHandleDereference debug_output;
       if (ref != NULL) {
         ref->PrintTo(&stream);
       } else {
@@ -11145,14 +11145,14 @@ void HTracer::TraceCompilation(CompilationInfo* info) {
 
 void HTracer::TraceLithium(const char* name, LChunk* chunk) {
   ASSERT(!FLAG_parallel_recompilation);
-  ALLOW_HANDLE_DEREF(chunk->isolate(), "debug output");
+  AllowDeferredHandleDereference debug_output;
   Trace(name, chunk->graph(), chunk);
 }
 
 
 void HTracer::TraceHydrogen(const char* name, HGraph* graph) {
   ASSERT(!FLAG_parallel_recompilation);
-  ALLOW_HANDLE_DEREF(graph->isolate(), "debug output");
+  AllowDeferredHandleDereference debug_output;
   Trace(name, graph, NULL);
 }