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

ui/gfx/render_text.cc

 // 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.
 
 #include "ui/gfx/render_text.h"
 
 #include <algorithm>
 #include <climits>
 
 #include "base/command_line.h"
@@ skipping 384 matching lines @@
   paint->setSubpixelText(params.subpixel_positioning);
   paint->setAutohinted(params.autohinter);
   paint->setHinting(FontRenderParamsHintingToSkPaintHinting(params.hinting));
 }
 
 }  // namespace internal
 
 RenderText::~RenderText() {
 }
 
+// static
 RenderText* RenderText::CreateInstance() {
 #if defined(OS_MACOSX)
   static const bool use_native =
       !base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnableHarfBuzzRenderText);
   if (use_native)
     return new RenderTextMac;
 #endif  // defined(OS_MACOSX)
   return new RenderTextHarfBuzz;
 }
 
+// static
 RenderText* RenderText::CreateInstanceForEditing() {
   return new RenderTextHarfBuzz;
 }
 
 void RenderText::SetText(const base::string16& text) {
   DCHECK(!composition_range_.IsValid());
   if (text_ == text)
     return;
   text_ = text;
 
@@ skipping 284 matching lines @@
 
 base::i18n::TextDirection RenderText::GetDisplayTextDirection() {
   return GetTextDirection(GetDisplayText());
 }
 
 VisualCursorDirection RenderText::GetVisualDirectionOfLogicalEnd() {
   return GetDisplayTextDirection() == base::i18n::LEFT_TO_RIGHT ?
       CURSOR_RIGHT : CURSOR_LEFT;
 }
 
+const base::string16& RenderText::GetAccessibleText() {
+  return layout_text_;

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

I think this should work as-is, since |layout_text_| is updated immediately on
each call to OnTextAttributeChanged, but I'm CC'ing oshima just in case, as per
the header comment for layout_text():
  // NOTE: The value of these accessors may be stale. Please make sure
  // that these fields are up-to-date before accessing them.

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

This method was removed.

+}
+
 SizeF RenderText::GetStringSizeF() {
   return GetStringSize();
 }
 
 float RenderText::GetContentWidthF() {
   const float string_size = GetStringSizeF().width();
   // The cursor is drawn one pixel beyond the int-enclosed text bounds.
   return cursor_enabled_ ? std::ceil(string_size) + 1 : string_size;
 }
 
@@ skipping 356 matching lines @@
 
 HorizontalAlignment RenderText::GetCurrentHorizontalAlignment() {
   if (horizontal_alignment_ != ALIGN_TO_HEAD)
     return horizontal_alignment_;
   return GetDisplayTextDirection() == base::i18n::RIGHT_TO_LEFT ?
       ALIGN_RIGHT : ALIGN_LEFT;
 }
 
 Vector2d RenderText::GetAlignmentOffset(size_t line_number) {
   // TODO(ckocagil): Enable |lines_| usage on RenderTextMac.
-  if (multiline_)
+  if (MultilineSupported() && multiline_)
     DCHECK_LT(line_number, lines_.size());
   Vector2d offset;
   HorizontalAlignment horizontal_alignment = GetCurrentHorizontalAlignment();
   if (horizontal_alignment != ALIGN_LEFT) {
     const int width = multiline_ ?
         std::ceil(lines_[line_number].size.width()) +
         (cursor_enabled_ ? 1 : 0) :
         GetContentWidth();
     offset.set_x(display_rect().width() - width);
     // Put any extra margin pixel on the left to match legacy behavior.
@@ skipping 346 matching lines @@
 
   SetDisplayOffset(display_offset_.x() + delta_x);
 }
 
 void RenderText::DrawSelection(Canvas* canvas) {
   for (const Rect& s : GetSubstringBounds(selection()))
     canvas->FillRect(s, selection_background_focused_color_);
 }
 
 }  // namespace gfx