Support merged Dart-JS callstacks

Source/bindings/common/StackTrace.h

Index: Source/bindings/common/StackTrace.h
diff --git a/Source/bindings/common/StackTrace.h b/Source/bindings/common/StackTrace.h
index 758c35d3e127d6a14e74c8712d9972b5c802e1af..137dbf8cafacf0e9202b8f127ea7ae0f3d2b5c3d 100644
--- a/Source/bindings/common/StackTrace.h
+++ b/Source/bindings/common/StackTrace.h
@@ -32,6 +32,8 @@
 #define StackTrace_h
 
 #include "bindings/common/ScriptValue.h"
+#include "wtf/HashMap.h"
+
 #include <dart_debugger_api.h>
 
 namespace WebCore {
@@ -89,6 +91,30 @@ private:
     Dart_StackTrace m_dartStackTrace;
 };
 
+class StackTraces {
+public:
+    typedef HashMap<ScriptState*, StackTrace> StackTraceMap;
+    typedef StackTraceMap::iterator iterator;
+    typedef StackTraceMap::const_iterator const_iterator;
+
+    StackTraces() { }
+    StackTraces(StackTrace, ScriptState*);
+
+    StackTrace lookup(ScriptState*) const;
+    void add(const StackTrace&, ScriptState*);
+    void add(const StackTraces&);
+
+    bool isNull() const { return m_traces.isEmpty(); }
+
+    iterator begin() { return m_traces.begin(); }
+    iterator end() { return m_traces.end(); }
+    const_iterator begin() const { return m_traces.begin(); }
+    const_iterator end() const { return m_traces.end(); }
+private:
+
+    StackTraceMap m_traces;
+};
+
 class ActivationFrame {
 public:
     explicit ActivationFrame()
@@ -111,6 +137,7 @@ public:
     }
 
     bool isJavaScript() const { return m_isJavaScript; }
+
     ScriptValue asJavaScript() const
     {
         ASSERT(m_isJavaScript);