Move GridCoordinate and GridSpan to a separate file

Source/core/rendering/style/GridCoordinate.h

+/*
+ * Copyright (C) 2013 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef GridCoordinate_h
+#define GridCoordinate_h
+
+#include "wtf/PassOwnPtr.h"
+
+namespace WebCore {
+
+// A span in a single direction (either rows or columns). Note that |initialPositionIndex|
+// and |finalPositionIndex| are grid areas' indexes, NOT grid lines'. Iterating over the
+// span should include both |initialPositionIndex| and |finalPositionIndex| to be correct.
+struct GridSpan {
+    static PassOwnPtr<GridSpan> create(size_t initialPosition, size_t finalPosition)
+    {
+        return adoptPtr(new GridSpan(initialPosition, finalPosition));
+    }
+
+    GridSpan(size_t initialPosition, size_t finalPosition)
+        : initialPositionIndex(initialPosition)
+        , finalPositionIndex(finalPosition)
+    {
+        ASSERT(initialPositionIndex <= finalPositionIndex);
+    }
+
+    size_t initialPositionIndex;
+    size_t finalPositionIndex;
+};
+
+// This represents a grid area that spans in both rows' and columns' direction.
+struct GridCoordinate {
+    // HashMap requires a default constuctor.
+    GridCoordinate()
+        : columns(0, 0)
+        , rows(0, 0)
+    {
+    }
+
+    GridCoordinate(const GridSpan& r, const GridSpan& c)
+        : columns(c)
+        , rows(r)
+    {
+    }
+
+    GridSpan columns;
+    GridSpan rows;
+};
+
+} // namespace WebCore
+
+#endif // GridCoordinate_h