Enable per thread heap on parser thread

third_party/WebKit/Source/core/html/parser/HTMLParserThread.cpp

Index: third_party/WebKit/Source/core/html/parser/HTMLParserThread.cpp
diff --git a/third_party/WebKit/Source/core/html/parser/HTMLParserThread.cpp b/third_party/WebKit/Source/core/html/parser/HTMLParserThread.cpp
index da86d28de94e563b1eb0d1931bd307c5e645e94f..e7dd14706adfb9ba44907aa2c1043c84d858f697 100644
--- a/third_party/WebKit/Source/core/html/parser/HTMLParserThread.cpp
+++ b/third_party/WebKit/Source/core/html/parser/HTMLParserThread.cpp
@@ -84,7 +84,7 @@ void HTMLParserThread::postTask(std::unique_ptr<CrossThreadClosure> closure) {
   ASSERT(isMainThread());
   if (!m_thread) {
     m_thread = WebThreadSupportingGC::create("HTMLParserThread",
-                                             BlinkGC::MainThreadHeapMode);
+                                             BlinkGC::PerThreadHeapMode);
     postTask(crossThreadBind(&HTMLParserThread::setupHTMLParserThread,
                              crossThreadUnretained(this)));
   }