RenderTextHarfBuzz: Try fallback fonts of the Uniscribe font while shaping

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 1c6f902d936fb435827912df67561e1d1af51c51..69b420d69cf1e0ad5b0ba5ff09ade670fb292bbf 100644
--- a/ui/gfx/render_text_unittest.cc
+++ b/ui/gfx/render_text_unittest.cc
@@ -16,6 +16,7 @@
 #include "ui/gfx/break_list.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/font.h"
+#include "ui/gfx/platform_font_win.h"
 #include "ui/gfx/render_text_harfbuzz.h"
 
 #if defined(OS_WIN)
@@ -30,6 +31,7 @@
 using base::ASCIIToUTF16;
 using base::UTF8ToUTF16;
 using base::WideToUTF16;
+using base::WideToUTF8;
 
 namespace gfx {
 
@@ -2326,4 +2328,24 @@ TEST_F(RenderTextTest, StringFitsOwnWidth) {
   EXPECT_EQ(kString, render_text->GetLayoutText());
 }
 
+// Ensure that the fallback fonts of the Uniscribe font are tried for shaping.
+#if defined(OS_WIN)
+TEST_F(RenderTextTest, HarfBuzz_UniscribeFallback) {
+  RenderTextHarfBuzz render_text;
+  PlatformFontWin* font_win = new PlatformFontWin("Meiryo", 12);
+  // Japanese name for Meiryo. This name won't be found in the system's linked
+  // fonts, forcing RTHB to try the Uniscribe font and its fallbacks.
+  font_win->font_ref_->font_name_ = WideToUTF8(L"\x30e1\x30a4\x30ea\x30aa");
+  Font font(font_win);
+  FontList font_list(font);
+
+  render_text.SetFontList(font_list);
+  // Korean character "han".
+  render_text.SetText(WideToUTF16(L"\xd55c"));
+  render_text.EnsureLayout();
+  ASSERT_EQ(1U, render_text.runs_.size());
+  EXPECT_EQ(0U, render_text.runs_[0]->CountMissingGlyphs());
+}
+#endif  // defined(OS_WIN)
+
 }  // namespace gfx