Moved MQ parsing block tracking to tokenizer

Source/core/css/parser/MediaQueryBlockWatcher.cpp

Index: Source/core/css/parser/MediaQueryBlockWatcher.cpp
diff --git a/Source/core/css/parser/MediaQueryBlockWatcher.cpp b/Source/core/css/parser/MediaQueryBlockWatcher.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..fdceea230d04eaa4a2f2a139aef017cf699d0810
--- /dev/null
+++ b/Source/core/css/parser/MediaQueryBlockWatcher.cpp
@@ -0,0 +1,28 @@
+// Copyright 2014 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 "core/css/parser/MediaQueryBlockWatcher.h"
+
+#include "core/css/parser/MediaQueryToken.h"
+
+namespace WebCore {
+
+MediaQueryBlockWatcher::MediaQueryBlockWatcher()
+    : m_blockLevel(0)
+{
+}
+
+void MediaQueryBlockWatcher::handleToken(const MediaQueryToken& token)
+{
+    if (token.blockType() == MediaQueryToken::BlockStart) {
+        ++m_blockLevel;
+    } else if (token.blockType() == MediaQueryToken::BlockEnd) {
+        ASSERT(m_blockLevel);
+        --m_blockLevel;
+    }
+}
+
+} // namespace
+