Make ScriptStreamer and dependents Oilpan friendly.

Source/bindings/core/v8/ScriptSourceCode.cpp

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "bindings/core/v8/ScriptSourceCode.h"
+
+namespace blink {
+
+ScriptSourceCode::ScriptSourceCode()
+    : m_resource(0)
+    , m_startPosition(TextPosition::minimumPosition())
+{
+}
+
+ScriptSourceCode::ScriptSourceCode(const String& source, const KURL& url, const TextPosition& startPosition)
+    : m_source(source)
+    , m_resource(0)
+    , m_url(url)
+    , m_startPosition(startPosition)
+{
+    treatNullSourceAsEmpty();
+    if (!m_url.isEmpty())
+        m_url.removeFragmentIdentifier();
+}
+
+ScriptSourceCode::ScriptSourceCode(ScriptResource* resource)
+    : m_source(resource->script())
+    , m_resource(resource)
+    , m_startPosition(TextPosition::minimumPosition())
+{
+    treatNullSourceAsEmpty();
+}
+
+ScriptSourceCode::ScriptSourceCode(PassRefPtrWillBeRawPtr<ScriptStreamer> streamer, ScriptResource* resource)
+    : m_source(resource->script())
+    , m_resource(resource)
+    , m_streamer(streamer)
+    , m_startPosition(TextPosition::minimumPosition())
+{
+    treatNullSourceAsEmpty();
+}
+
+ScriptSourceCode::~ScriptSourceCode()
+{
+}
+
+void ScriptSourceCode::trace(Visitor* visitor)
+{
+    visitor->trace(m_streamer);
+}
+
+const KURL& ScriptSourceCode::url() const
+{
+    if (m_url.isEmpty() && m_resource) {
+        m_url = m_resource->response().url();
+        if (!m_url.isEmpty())
+            m_url.removeFragmentIdentifier();
+    }
+    return m_url;
+}
+
+void ScriptSourceCode::treatNullSourceAsEmpty()
+{
+    // ScriptSourceCode allows for the representation of the null/not-there-really ScriptSourceCode value.
+    // Encoded by way of a m_source.isNull() being true, with the nullary constructor to be used to
+    // construct such a value.
+    //
+    // Should the other constructors be passed a null string, that is interpreted as representing
+    // the empty script. Consequently, we need to disambiguate between such null string occurrences.
+    // Do that by converting the latter case's null strings into empty ones.
+    if (m_source.isNull())
+        m_source = "";
+}
+
+} // namespace blink