Fix assertion failure in ScriptRegexp::match

Source/bindings/core/v8/ScriptRegexp.cpp

Index: Source/bindings/core/v8/ScriptRegexp.cpp
diff --git a/Source/bindings/core/v8/ScriptRegexp.cpp b/Source/bindings/core/v8/ScriptRegexp.cpp
index 9a357a4a54d58eff9a3b2bd6bac04bdd4b55d911..5a59c7483531b54cd0db795d6b420362508596db 100644
--- a/Source/bindings/core/v8/ScriptRegexp.cpp
+++ b/Source/bindings/core/v8/ScriptRegexp.cpp
@@ -33,6 +33,7 @@
 #include "bindings/core/v8/V8PerIsolateData.h"
 #include "bindings/core/v8/V8ScriptRunner.h"
 #include "platform/ScriptForbiddenScope.h"
+#include "wtf/Optional.h"
 
 namespace blink {
 
@@ -67,7 +68,9 @@ int ScriptRegexp::match(const String& string, int startFrom, int* matchLength) c
     if (string.length() > INT_MAX)
         return -1;
 
-    ScriptForbiddenScope::AllowUserAgentScript allowScript;
+    Optional<ScriptForbiddenScope::AllowUserAgentScript> allowScript;
+    if (isMainThread())
+        allowScript.emplace();

[haraken, 2015/08/27 23:46:40]

Would it make sense to move the Optional into AllowUserAgentScript and make this
the default behavior of AllowUserAgentScript?

[yurys, 2015/08/27 23:56:49]

Done. I'm not sure what was the reason to have all this machinery only on the
main thread.

 
     v8::Isolate* isolate = v8::Isolate::GetCurrent();
     v8::HandleScope handleScope(isolate);