Break runs by clusters rather than iteration over code points

ui/gfx/render_text_unittest.cc

Index: ui/gfx/render_text_unittest.cc
diff --git a/ui/gfx/render_text_unittest.cc b/ui/gfx/render_text_unittest.cc
index 42825579ec6cb0b68fe701de431a2c1444d5c1f7..54ba5317a9dc0722bbd226f2b9f2ca759d30ac94 100644
--- a/ui/gfx/render_text_unittest.cc
+++ b/ui/gfx/render_text_unittest.cc
@@ -2577,6 +2577,21 @@ TEST_F(RenderTextTest, HarfBuzz_EmptyRun) {
   EXPECT_EQ(Range(0, 0), glyphs);
 }
 
+// Ensure the line breaker doesn't compute the word's width bigger than the
+// actual size. See http://crbug.com/470073
+TEST_F(RenderTextTest, HarfBuzz_WordWidthWithDiacritics) {
+  RenderTextHarfBuzz render_text;
+  const base::string16 kWord = WideToUTF16(L"\u0906\u092A\u0915\u0947 ");
+  render_text.SetText(kWord);
+  gfx::SizeF text_size = render_text.GetStringSizeF();

[msw, 2015/03/25 20:25:16]

nit: const

[Jun Mukai, 2015/03/25 21:50:05]

Done.

+
+  render_text.SetText(kWord + kWord);

[msw, 2015/03/25 20:25:16]

nit: after this, but before SetDisplayRect, can you test something like:
  EXPECT_EQ(text_size.width() * 2, render_text.GetStringSizeF().width());

[Jun Mukai, 2015/03/25 21:50:05]

Done.

+  render_text.SetMultiline(true);
+  render_text.SetDisplayRect(gfx::Rect(0, 0, text_size.width(), 0));

[msw, 2015/03/25 20:25:16]

nit: instead of setting the display rect, can you add a '\n' char?

[Jun Mukai, 2015/03/25 21:50:05]

'\n' doesn't work well in this case, since RTHB splits the text into different
runs, this CL wants to verify the line breaks in a run.

[msw, 2015/03/25 22:51:44]

Acknowledged.

+  EXPECT_EQ(text_size.width(), render_text.GetStringSizeF().width());
+  EXPECT_EQ(text_size.height() * 2, render_text.GetStringSizeF().height());
+}
+
 // Ensure a string fits in a display rect with a width equal to the string's.
 TEST_F(RenderTextTest, StringFitsOwnWidth) {
   scoped_ptr<RenderText> render_text(RenderText::CreateInstance());