Improve RenderTextWin font fallback.

ui/gfx/render_text_unittest.cc

Index: ui/gfx/render_text_unittest.cc
===================================================================
--- ui/gfx/render_text_unittest.cc	(revision 113627)
+++ ui/gfx/render_text_unittest.cc	(working copy)
@@ -8,6 +8,10 @@
 #include "base/utf_string_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if defined(OS_WIN)
+#include "base/win/windows_version.h"
+#endif
+
 namespace gfx {
 
 class RenderTextTest : public testing::Test {
@@ -543,6 +547,119 @@
 }
 #endif
 
+TEST_F(RenderTextTest, GraphemePositions) {
+  // LTR 2-character grapheme, LTR abc, LTR 2-character grapheme.
+  const string16 kText1 = WideToUTF16(L"\x0915\x093f"L"abc"L"\x0915\x093f");
+
+  // LTR ab, LTR 2-character grapheme, LTR cd.
+  const string16 kText2 = WideToUTF16(L"ab"L"\x0915\x093f"L"cd");
+
+  struct {
+    string16 text;
+    size_t index;
+    size_t expected_previous;
+    size_t expected_next;
+  } cases[] = {
+    { string16(), 0, 0, 0 },
+    { string16(), 1, 0, 0 },
+    { string16(), 50, 0, 0 },
+    { kText1, 0, 0, 2 },
+    { kText1, 1, 0, 2 },
+    { kText1, 2, 0, 3 },
+    { kText1, 3, 2, 4 },
+    { kText1, 4, 3, 5 },
+    { kText1, 5, 4, 7 },
+    { kText1, 6, 5, 7 },
+    { kText1, 7, 5, 7 },
+    { kText1, 8, 7, 7 },
+    { kText1, 50, 7, 7 },
+    { kText2, 0, 0, 1 },
+    { kText2, 1, 0, 2 },
+    { kText2, 2, 1, 4 },
+    { kText2, 3, 2, 4 },
+    { kText2, 4, 2, 5 },
+    { kText2, 5, 4, 6 },
+    { kText2, 6, 5, 6 },
+    { kText2, 7, 6, 6 },
+    { kText2, 50, 6, 6 },
+  };
+
+  // TODO(asvitkine): Disable tests that fail on XP bots due to lack of complete
+  //                  font support for some scripts - http://crbug.com/106450
+#if defined(OS_WIN)
+  if (base::win::GetVersion() < base::win::VERSION_VISTA)
+    return;
+#endif
+
+  scoped_ptr<RenderText> render_text(RenderText::CreateRenderText());
+  for (size_t i = 0; i < ARRAYSIZE_UNSAFE(cases); i++) {
+    render_text->SetText(cases[i].text);
+
+    size_t next = render_text->GetIndexOfNextGrapheme(cases[i].index);
+    EXPECT_EQ(cases[i].expected_next, next);
+    EXPECT_TRUE(render_text->IsCursorablePosition(next));
+
+    size_t previous = render_text->GetIndexOfPreviousGrapheme(cases[i].index);
+    EXPECT_EQ(cases[i].expected_previous, previous);
+    EXPECT_TRUE(render_text->IsCursorablePosition(previous));
+  }
+}
+
+TEST_F(RenderTextTest, SelectionModels) {
+  // Simple Latin text.
+  const string16 kLatin = WideToUTF16(L"abc");
+  // LTR 2-character grapheme.
+  const string16 kLTRGrapheme = WideToUTF16(L"\x0915\x093f");
+  // LTR 2-character grapheme, LTR a, LTR 2-character grapheme.
+  const string16 kHindiLatin = WideToUTF16(L"\x0915\x093f"L"a"L"\x0915\x093f");
+  // RTL 2-character grapheme.
+  const string16 kRTLGrapheme = WideToUTF16(L"\x05e0\x05b8");
+  // RTL 2-character grapheme, LTR a, RTL 2-character grapheme.
+  const string16 kHebrewLatin = WideToUTF16(L"\x05e0\x05b8"L"a"L"\x05e0\x05b8");
+
+  struct {
+    string16 text;
+    size_t expected_left_end_caret;
+    SelectionModel::CaretPlacement expected_left_end_placement;
+    size_t expected_right_end_caret;
+    SelectionModel::CaretPlacement expected_right_end_placement;
+  } cases[] = {
+    { string16(), 0, SelectionModel::LEADING, 0, SelectionModel::LEADING },
+    { kLatin, 0, SelectionModel::LEADING, 2, SelectionModel::TRAILING },
+    { kLTRGrapheme, 0, SelectionModel::LEADING, 0, SelectionModel::TRAILING },
+    { kHindiLatin, 0, SelectionModel::LEADING, 3, SelectionModel::TRAILING },
+    { kRTLGrapheme, 0, SelectionModel::TRAILING, 0, SelectionModel::LEADING },
+#if defined(OS_LINUX)
+    // On Linux, the whole string is displayed RTL, rather than individual runs.
+    { kHebrewLatin, 3, SelectionModel::TRAILING, 0, SelectionModel::LEADING },
+#else
+    { kHebrewLatin, 0, SelectionModel::TRAILING, 3, SelectionModel::LEADING },
+#endif
+  };
+
+  // TODO(asvitkine): Disable tests that fail on XP bots due to lack of complete
+  //                  font support for some scripts - http://crbug.com/106450
+#if defined(OS_WIN)
+  if (base::win::GetVersion() < base::win::VERSION_VISTA)
+    return;
+#endif
+
+  scoped_ptr<RenderText> render_text(RenderText::CreateRenderText());
+  for (size_t i = 0; i < ARRAYSIZE_UNSAFE(cases); i++) {
+    render_text->SetText(cases[i].text);
+
+    SelectionModel model = render_text->LeftEndSelectionModel();
+    EXPECT_EQ(cases[i].expected_left_end_caret, model.caret_pos());
+    EXPECT_TRUE(render_text->IsCursorablePosition(model.caret_pos()));
+    EXPECT_EQ(cases[i].expected_left_end_placement, model.caret_placement());
+
+    model = render_text->RightEndSelectionModel();
+    EXPECT_EQ(cases[i].expected_right_end_caret, model.caret_pos());
+    EXPECT_TRUE(render_text->IsCursorablePosition(model.caret_pos()));
+    EXPECT_EQ(cases[i].expected_right_end_placement, model.caret_placement());
+  }
+}
+
 TEST_F(RenderTextTest, MoveCursorLeftRightWithSelection) {
   scoped_ptr<RenderText> render_text(RenderText::CreateRenderText());
   render_text->SetText(WideToUTF16(L"abc\x05d0\x05d1\x05d2"));