Support ServiceWorker created request objects.

Source/platform/network/HTTPHeaderMap.h

Index: Source/platform/network/HTTPHeaderMap.h
diff --git a/Source/platform/network/HTTPHeaderMap.h b/Source/platform/network/HTTPHeaderMap.h
index f18cec05bd778e4e9dfc46a7482781a3ae7a97e0..94c59917dfe20c1c300ff052cd3b0332375c4022 100644
--- a/Source/platform/network/HTTPHeaderMap.h
+++ b/Source/platform/network/HTTPHeaderMap.h
@@ -64,7 +64,8 @@ public:
     AddResult set(const AtomicString& k, const AtomicString& v) { return m_headers.set(k, v); }
     AddResult add(const AtomicString& k, const AtomicString& v) { return m_headers.add(k, v); }
     void remove(const AtomicString& k) { m_headers.remove(k); }
-    bool operator!=(const HTTPHeaderMap &rhs) const { return m_headers != rhs.m_headers; }
+    bool operator!=(const HTTPHeaderMap& rhs) const { return m_headers != rhs.m_headers; }
+    bool operator==(const HTTPHeaderMap& rhs) const { return m_headers == rhs.m_headers; }
 
     // Alternate accessors that are faster than converting the char* to AtomicString first.
     bool contains(const char*) const;