Reduce the number of text reshaping in RenderText

Short Design Doc: http://goo.gl/w6Q9k8
1) Compute ElidedText on demand
2) Separate elided text and non elided text. Create elided text and runs only when necessary.
3) Use known width in RenderText::Elide
4) Don't reshape to get GetGraphemeIterator.

This CL also adds a few trace event so that we can identify the UI jank caused by text rendering performance.

BUG=451459
R=msw@chromium.org

Review URL: https://codereview.chromium.org/916203002

Cr-Commit-Position: refs/heads/master@{#316375}

chrome/browser/ui/views/omnibox/omnibox_result_view.cc

@@ -279,7 +279,7 @@ int OmniboxResultView::DrawRenderText(
     // vertically stack the ellipsis by restricting the end edge (right_x).
     const bool is_ui_rtl = base::i18n::IsRTL();
     const bool is_match_contents_rtl =
-        (render_text->GetTextDirection() == base::i18n::RIGHT_TO_LEFT);
+        (render_text->GetDisplayTextDirection() == base::i18n::RIGHT_TO_LEFT);
     const int offset =
         GetDisplayOffset(match, is_ui_rtl, is_match_contents_rtl);
 

ui/gfx/canvas_skia.cc

@@ -292,7 +292,7 @@ void Canvas::DrawStringRectWithShadows(const base::string16& text,
     // for LTR text. RTL text is still elided (on the left) with "...".
     if (elide_text) {
       render_text->SetText(adjusted_text);
-      if (render_text->GetTextDirection() == base::i18n::LEFT_TO_RIGHT) {
+      if (render_text->GetDisplayTextDirection() == base::i18n::LEFT_TO_RIGHT) {
         render_text->SetElideBehavior(FADE_TAIL);
         elide_text = false;
       }