Cache gfx::RenderText instances in views::Label.

ui/gfx/render_text.h

 // Copyright (c) 2012 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_RENDER_TEXT_H_
 #define UI_GFX_RENDER_TEXT_H_
 
 #include <algorithm>
 #include <cstring>
 #include <string>
@@ skipping 238 matching lines @@
   // is cleared and only the last set index will be revealed. If |index| is -1
   // or out of range, no char will be revealed. The revealed index is also
   // cleared when SetText or SetObscured is called.
   void SetObscuredRevealIndex(int index);
 
   // TODO(ckocagil): Multiline text rendering is currently only supported on
   // Windows. Support other platforms.
   bool multiline() const { return multiline_; }
   void SetMultiline(bool multiline);
 
+  // Returns true if this instance supports multiline rendering.
+  virtual bool MultilineSupported() const = 0;
+
   // TODO(ckocagil): Add vertical alignment and line spacing support instead.
   int min_line_height() const { return min_line_height_; }
   void SetMinLineHeight(int line_height);
 
   // Set the maximum length of the layout text, not the actual text.
   // A |length| of 0 forgoes a hard limit, but does not guarantee proper
   // functionality of very long strings. Applies to subsequent SetText calls.
   // WARNING: Only use this for system limits, it lacks complex text support.
   void set_truncate_length(size_t length) { truncate_length_ = length; }
 
   // The layout text will be elided to fit |display_rect| using this behavior.

[msw, 2015/02/25 23:54:26]

nit: please update this comment: s/layout/display/

[Jun Mukai, 2015/02/26 01:40:24]

Done.

   void SetElideBehavior(ElideBehavior elide_behavior);
   ElideBehavior elide_behavior() const { return elide_behavior_; }
 
   const Rect& display_rect() const { return display_rect_; }
   void SetDisplayRect(const Rect& r);
 
   bool subpixel_rendering_suppressed() const {
     return subpixel_rendering_suppressed_;
   }
   void set_subpixel_rendering_suppressed(bool suppressed) {
@@ skipping 67 matching lines @@
   DirectionalityMode directionality_mode() const {
       return directionality_mode_;
   }
   base::i18n::TextDirection GetDisplayTextDirection();
 
   // Returns the visual movement direction corresponding to the logical end
   // of the text, considering only the dominant direction returned by
   // |GetDisplayTextDirection()|, not the direction of a particular run.
   VisualCursorDirection GetVisualDirectionOfLogicalEnd();
 
+  // Returns the un-elided text, but replaced when obscured.

[msw, 2015/02/25 23:54:26]

nit: consider a comment matching the format of that for GetDisplayText():
"Returns the text used for layout, which may be truncated or obscured, but it
will not be elided."

[Jun Mukai, 2015/02/26 01:40:25]

Removed this, adding this was my mistake, Because Label's |render_text_| is not
elided at all, this method is not necessary.

+  const base::string16& GetAccessibleText();

[msw, 2015/02/25 23:54:26]

Let's call this GetLayoutText().

[Jun Mukai, 2015/02/26 01:40:25]

ditto

+
   // Returns the text used to display, which may be obscured, truncated or
   // elided. The subclass may compute elided text on the fly, or use
   // precomputed the elided text.
   virtual const base::string16& GetDisplayText() = 0;
 
   // Returns the size required to display the current string (which is the
   // wrapped size in multiline mode). The returned size does not include space
   // reserved for the cursor or the offset text shadows.
   virtual Size GetStringSize() = 0;
 
@@ skipping 54 matching lines @@
   // supplied index is already at the boundary of the string.
   size_t IndexOfAdjacentGrapheme(size_t index,
                                  LogicalCursorDirection direction);
 
   // Return a SelectionModel with the cursor at the current selection's start.
   // The returned value represents a cursor/caret position without a selection.
   SelectionModel GetSelectionModelForSelectionStart();
 
   // Sets shadows to drawn with text.
   void set_shadows(const ShadowValues& shadows) { shadows_ = shadows; }
-  const ShadowValues& shadows() { return shadows_; }
+  const ShadowValues& shadows() const { return shadows_; }
 
   typedef std::pair<Font, Range> FontSpan;
   // For testing purposes, returns which fonts were chosen for which parts of
   // the text by returning a vector of Font and Range pairs, where each range
   // specifies the character range for which the corresponding font has been
   // chosen.
   virtual std::vector<FontSpan> GetFontSpansForTesting() = 0;
 
   // Gets the horizontal bounds (relative to the left of the text, not the view)
   // of the glyph starting at |index|. If the glyph is RTL then the returned
@@ skipping 327 matching lines @@
   // Lines computed by EnsureLayout. These should be invalidated upon
   // OnLayoutTextAttributeChanged and OnDisplayTextAttributeChanged calls.
   std::vector<internal::Line> lines_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderText);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RENDER_TEXT_H_