Enable subpixel positioning for UI

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 859689b5febce093495cea438fc1b3a3dd0d523d..42976a5c0e00433754831bd0537910b7b6de751f 100644
--- a/ui/gfx/render_text_unittest.cc
+++ b/ui/gfx/render_text_unittest.cc
@@ -2373,4 +2373,35 @@ TEST_F(RenderTextTest, HarfBuzz_UniscribeFallback) {
 }
 #endif  // defined(OS_WIN)
 
+// Ensure that the width reported by RenderText is sufficient for drawing. Draws
+// to a canvas and checks whether any pixel beyond the width is colored.
+TEST_F(RenderTextTest, TextDoesntClip) {
+  const wchar_t* kTestStrings[] = { L"Save", L"Remove", L"TEST", L"W", L"WWW" };
+
+  skia::RefPtr<SkCanvas> sk_canvas =
+      skia::AdoptRef(SkCanvas::NewRasterN32(300, 50));
+  scoped_ptr<Canvas> canvas(
+      Canvas::CreateCanvasWithoutScaling(sk_canvas.get(), 1.0f));
+  scoped_ptr<RenderText> render_text(RenderText::CreateInstance());
+  render_text->SetDisplayRect(Rect(300, 50));
+  render_text->SetHorizontalAlignment(gfx::ALIGN_LEFT);
+  render_text->SetColor(SK_ColorBLACK);
+
+  for (size_t i = 0; i < arraysize(kTestStrings); ++i) {
+    sk_canvas->clear(SK_ColorWHITE);
+    render_text->SetText(WideToUTF16(kTestStrings[i]));
+    render_text->SetStyle(BOLD, true);
+    render_text->Draw(canvas.get());
+    int width = render_text->GetStringSize().width();
+    ASSERT_LT(width, 300);
+    const uint32* buffer = static_cast<const uint32*>(
+        sk_canvas->peekPixels(NULL, NULL));
+    ASSERT_NE(nullptr, buffer);
+    for (int y = 0; y < 50; ++y) {
+      EXPECT_EQ(SK_ColorWHITE, buffer[width + y * 300])
+          << "String: " << kTestStrings[i];
+    }
+  }
+}
+
 }  // namespace gfx