Add a unit tests for RenderText::FindCursorPosition.

ui/gfx/render_text_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/render_text.h"
 
 #include <algorithm>
 
 #include "base/format_macros.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 928 matching lines @@
     EXPECT_EQ(1U, render_text->cursor_position());
     // Although selection bounds may be set within a multi-character grapheme,
     // cursor movement (e.g. via arrow key) should avoid those indices.
     render_text->MoveCursor(CHARACTER_BREAK, CURSOR_LEFT, false);
     EXPECT_EQ(0U, render_text->cursor_position());
     render_text->MoveCursor(CHARACTER_BREAK, CURSOR_RIGHT, false);
     EXPECT_EQ(2U, render_text->cursor_position());
   }
 }
 
+TEST_F(RenderTextTest, FindCursorPosition) {
+  const wchar_t* kTestStrings[] = { kLtrRtl, kLtrRtlLtr, kRtlLtr, kRtlLtrRtl };
+  scoped_ptr<RenderText> render_text(RenderText::CreateInstance());
+  render_text->SetDisplayRect(Rect(0, 0, 100, 20));
+  for (size_t i = 0; i < arraysize(kTestStrings); ++i) {
+    SCOPED_TRACE(base::StringPrintf("Testing case[%" PRIuS "]", i));
+    render_text->SetText(WideToUTF16(kTestStrings[i]));
+    render_text->EnsureLayout();

[Alexei Svitkine (slow), 2014/05/12 15:23:27]

GetGlyphBounds() and FindCursorPosition() are both public methods.

So you shouldn't need to call the protected EnsureLayout() method here before
calling those. If this currently causes a crash/dcheck, than that's a bug and
should be fixed.

After you remove the EnsureLayout() call, I think you should also be able to
remove the friend test declaration for this test, since it will be using public
methods only.

[msw, 2014/05/12 17:15:56]

Done.

+    for(size_t j = 0; j < render_text->text().length(); ++j) {
+      const Range range(render_text->GetGlyphBounds(j));
+      // Test a point just inside the leading edge of the glyph bounds.
+      int x = range.is_reversed() ? range.GetMax() - 1 : range.GetMin() + 1;
+      EXPECT_EQ(j, render_text->FindCursorPosition(Point(x, 0)).caret_pos());
+    }
+  }
+}
+
 TEST_F(RenderTextTest, EdgeSelectionModels) {
   // Simple Latin text.
   const base::string16 kLatin = WideToUTF16(L"abc");
   // LTR 2-character grapheme.
   const base::string16 kLTRGrapheme = WideToUTF16(L"\x0915\x093f");
   // LTR 2-character grapheme, LTR a, LTR 2-character grapheme.
   const base::string16 kHindiLatin =
       WideToUTF16(L"\x0915\x093f" L"a" L"\x0915\x093f");
   // RTL 2-character grapheme.
   const base::string16 kRTLGrapheme = WideToUTF16(L"\x05e0\x05b8");
@@ skipping 785 matching lines @@
             render_text->GetUpdatedCursorBounds().x());
 
   // Reset the application default text direction to LTR.
   SetRTL(was_rtl);
   EXPECT_EQ(was_rtl, base::i18n::IsRTL());
 }
 #endif  // !defined(OS_MACOSX)
 
 // Changing colors between or inside ligated glyphs should not break shaping.
 TEST_F(RenderTextTest, SelectionKeepsLigatures) {
-  const wchar_t* kTestStrings[] = {
-    L"\x644\x623",
-    L"\x633\x627"
-  };
-
+  const wchar_t* kTestStrings[] = { L"\x644\x623", L"\x633\x627" };
   scoped_ptr<RenderText> render_text(RenderText::CreateInstance());
   render_text->set_selection_color(SK_ColorRED);
   Canvas canvas;
 
   for (size_t i = 0; i < arraysize(kTestStrings); ++i) {
     render_text->SetText(WideToUTF16(kTestStrings[i]));
     const int expected_width = render_text->GetStringSize().width();
     render_text->MoveCursorTo(SelectionModel(Range(0, 1), CURSOR_FORWARD));
     EXPECT_EQ(expected_width, render_text->GetStringSize().width());
-    // Draw the text. It shouldn't hit any DCHECKs or crash.
-    // See http://crbug.com/214150
+    // Drawing the text should not DCHECK or crash; see http://crbug.com/262119
     render_text->Draw(&canvas);
     render_text->MoveCursorTo(SelectionModel(0, CURSOR_FORWARD));
   }
 }
 
 #if defined(OS_WIN)
 // Ensure strings wrap onto multiple lines for a small available width.
 TEST_F(RenderTextTest, Multiline_MinWidth) {
   const wchar_t* kTestStrings[] = { kWeak, kLtr, kLtrRtl, kLtrRtlLtr, kRtl,
                                     kRtlLtr, kRtlLtrRtl };
@@ skipping 127 matching lines @@
   render_text->SetText(WideToUTF16(L"x \x25B6 y"));
   render_text->EnsureLayout();
   ASSERT_EQ(3U, render_text->runs_.size());
   EXPECT_EQ(Range(0, 2), render_text->runs_[0]->range);
   EXPECT_EQ(Range(2, 3), render_text->runs_[1]->range);
   EXPECT_EQ(Range(3, 5), render_text->runs_[2]->range);
 }
 #endif  // defined(OS_WIN)
 
 }  // namespace gfx