Add float version of gfx::Range

ui/gfx/range/range_f.h

Index: ui/gfx/range/range_f.h
diff --git a/ui/gfx/range/range_f.h b/ui/gfx/range/range_f.h
new file mode 100644
index 0000000000000000000000000000000000000000..49bc7601e32cd9062993e6c4903eead96c4b38d1
--- /dev/null
+++ b/ui/gfx/range/range_f.h
@@ -0,0 +1,82 @@
+// 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.
+
+#ifndef UI_GFX_RANGE_RANGE_F_H_
+#define UI_GFX_RANGE_RANGE_F_H_
+
+#include <ostream>
+#include <string>
+
+#include "base/basictypes.h"
+#include "ui/gfx/gfx_export.h"
+
+namespace gfx {
+
+// A float version of Range. RangeF is made of a start and end position; when
+// they are the same, the range is empty. Note that |start_| can be greater
+// than |end_| to respect the directionality of the range.
+class GFX_EXPORT RangeF {
+ public:
+  // Creates an empty range {0,0}.
+  RangeF();
+
+  // Initializes the range with a start and end.
+  RangeF(float start, float end);
+
+  // Initializes the range with the same start and end positions.
+  explicit RangeF(float position);
+
+  // Returns a range that is invalid, which is {float_max,float_max}.
+  static const RangeF InvalidRange();
+
+  // Checks if the range is valid through comparison to InvalidRange().
+  bool IsValid() const;
+
+  // Getters and setters.
+  float start() const { return start_; }
+  void set_start(float start) { start_ = start; }
+
+  float end() const { return end_; }
+  void set_end(float end) { end_ = end; }
+
+  // Returns the absolute value of the length.
+  float length() const {
+    const float length = end() - start();
+    return length >= 0 ? length : -length;
+  }
+
+  bool is_reversed() const { return start() > end(); }
+  bool is_empty() const { return start() == end(); }
+
+  // Returns the minimum and maximum values.
+  float GetMin() const;
+  float GetMax() const;
+
+  bool operator==(const RangeF& other) const;
+  bool operator!=(const RangeF& other) const;
+  bool EqualsIgnoringDirection(const RangeF& other) const;
+
+  // Returns true if this range intersects the specified |range|.
+  bool Intersects(const RangeF& range) const;
+
+  // Returns true if this range contains the specified |range|.
+  bool Contains(const RangeF& range) const;
+
+  // Computes the intersection of this range with the given |range|.
+  // If they don't intersect, it returns an InvalidRange().
+  // The returned range is always empty or forward (never reversed).
+  RangeF Intersect(const RangeF& range) const;
+
+  std::string ToString() const;
+
+ private:
+  float start_;
+  float end_;
+};
+
+GFX_EXPORT std::ostream& operator<<(std::ostream& os, const RangeF& range);
+
+}  // namespace gfx
+
+#endif  // UI_GFX_RANGE_RANGE_F_H_