Add views::RichLabel, a class which creates multi-line text with mixed

ui/views/controls/styled_label.h

+// Copyright 2013 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_VIEWS_CONTROLS_STYLED_LABEL_H_
+#define UI_VIEWS_CONTROLS_STYLED_LABEL_H_
+
+#include <map>
+#include <queue>
+
+#include "base/basictypes.h"
+#include "base/string16.h"
+#include "ui/base/range/range.h"
+#include "ui/gfx/size.h"
+#include "ui/views/controls/link_listener.h"
+#include "ui/views/view.h"
+
+namespace views {
+
+class Link;
+class StyledLabelListener;
+
+// A class which can apply mixed styles to a block of text. Currently, text is
+// always multiline, and the only style that may be applied is linkifying ranges
+// of text.
+class VIEWS_EXPORT StyledLabel : public View, public LinkListener {
+ public:
+  StyledLabel(const string16& text, StyledLabelListener* listener);
+  virtual ~StyledLabel();
+
+  // Marks the given range within |text_| as a link.
+  void AddLink(const ui::Range& range);
+
+  // View implementation:
+  virtual gfx::Insets GetInsets() const OVERRIDE;
+  virtual int GetHeightForWidth(int w) OVERRIDE;
+  virtual void Layout() OVERRIDE;
+
+  // LinkListener implementation:
+  virtual void LinkClicked(Link* source, int event_flags) OVERRIDE;
+
+ private:
+  struct LinkRange {
+    explicit LinkRange(const ui::Range& range) : range(range) {}
+    ~LinkRange() {}
+
+    bool operator<(const LinkRange& other) const;
+
+    ui::Range range;
+  };
+
+  // Calculates how to layout child views, creates them and sets their size
+  // and position. |width| is the horizontal space, in pixels, that the view
+  // has to work with. If |dry_run| is true, the view hierarchy is not touched.
+  // The return value is the height in pixels.
+  int CalculateAndDoLayout(int width, bool dry_run);
+
+  // The text to display.
+  string16 text_;
+
+  // The listener that will be informed of link clicks.
+  StyledLabelListener* listener_;
+
+  // The ranges that should be linkified, sorted by start position.
+  std::priority_queue<LinkRange> link_ranges_;
+
+  // A mapping from Link* control to the range it corresponds to in |text_|.
+  std::map<Link*, ui::Range> link_targets_;
+
+  // This variable saves the result of the last GetHeightForWidth call in order
+  // to avoid repeated calculation.
+  gfx::Size calculated_size_;
+
+  DISALLOW_COPY_AND_ASSIGN(StyledLabel);
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_CONTROLS_STYLED_LABEL_H_