[AiS] for desktop, two lines and font sytles

ui/gfx/render_text.cc

Index: ui/gfx/render_text.cc
diff --git a/ui/gfx/render_text.cc b/ui/gfx/render_text.cc
index 2b51d8aa8c75156871e18fda188ba726cad0c33a..9e75dafc44e81977f0890fa3ad30604559e6bcc7 100644
--- a/ui/gfx/render_text.cc
+++ b/ui/gfx/render_text.cc
@@ -445,21 +445,17 @@ void RenderText::SetText(const base::string16& text) {
   DCHECK(!composition_range_.IsValid());
   if (text_ == text)
     return;
-  text_ = text;
+  text_.clear();
+  AppendText(text);
 
-  // Adjust ranged styles, baselines, and colors to accommodate a new text
-  // length. Clear style ranges as they might break new text graphemes and apply
+  // Clear style ranges as they might break new text graphemes and apply
   // the first style to the whole text instead.
-  const size_t text_length = text_.length();
-  colors_.SetMax(text_length);
+  colors_.SetValue(colors_.breaks().begin()->second);
   baselines_.SetValue(baselines_.breaks().begin()->second);
-  baselines_.SetMax(text_length);
   for (size_t style = 0; style < NUM_TEXT_STYLES; ++style) {

[msw, 2015/03/18 18:03:37]

nit: inline this for a one-liner and remove loop curly-braces.
  for (size_t style = 0; style < NUM_TEXT_STYLES; ++style)
    styles_[style].SetValue(styles_[style].breaks().begin()->second)

[dschuyler, 2015/03/18 19:16:49]

Done.

     BreakList<bool>& break_list = styles_[style];
     break_list.SetValue(break_list.breaks().begin()->second);
-    break_list.SetMax(text_length);
   }
-  cached_bounds_and_offset_valid_ = false;
 
   // Reset selection model. SetText should always followed by SetSelectionModel
   // or SetCursorPosition in upper layer.
@@ -468,7 +464,19 @@ void RenderText::SetText(const base::string16& text) {
   // Invalidate the cached text direction if it depends on the text contents.
   if (directionality_mode_ == DIRECTIONALITY_FROM_TEXT)
     text_direction_ = base::i18n::UNKNOWN_DIRECTION;
+}
 
+void RenderText::AppendText(const base::string16& text) {
+  text_ += text;
+  // Adjust ranged styles and colors to accommodate a new text length.
+  const size_t text_length = text_.length();
+  colors_.SetMax(text_length);
+  baselines_.SetMax(text_length);
+  for (size_t style = 0; style < NUM_TEXT_STYLES; ++style) {
+    BreakList<bool>& break_list = styles_[style];

[msw, 2015/03/18 18:03:37]

ditto nit: inline this for a one-liner and remove loop curly-braces.
  for (size_t style = 0; style < NUM_TEXT_STYLES; ++style)
    styles_[style].SetMax(text_length)

[dschuyler, 2015/03/18 19:16:49]

Done.

+    break_list.SetMax(text_length);
+  }
+  cached_bounds_and_offset_valid_ = false;
   obscured_reveal_index_ = -1;
   OnTextAttributeChanged();

[msw, 2015/03/18 18:03:37]

+CC oshima... I think that calling this in the middle of SetText, before the
styles have been finalized, is insufficient. You'll probably need to call this
at the end of SetText, but calling it twice per SetText is likely to cause a
performance regression. I suppose you'll need to have a private
AppendText[Impl|Internal] (or something) that SetText and AppendText can call
that does everything above, except call OnTextAttributeChanged() (and perhaps
also modify cached_bounds_and_offset_valid_ and obscured_reveal_index_), then
have the two public functions do that separately.

[dschuyler, 2015/03/18 19:16:49]

I went ahead and separated out AppendText into a DoAppendText.

Done.

 }