RenderText: Add a test to ensure strings fit their own widths

This CL tests against regressions of http://crbug.com/402347

BUG=402347

Review URL: https://codereview.chromium.org/652573002

Cr-Commit-Position: refs/heads/master@{#299997}

ui/gfx/render_text.h

@@ -581,6 +581,7 @@ class GFX_EXPORT RenderText {
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, SameFontForParentheses);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, BreakRunsByUnicodeBlocks);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, PangoAttributes);
+  FRIEND_TEST_ALL_PREFIXES(RenderTextTest, StringFitsOwnWidth);
 
   // Creates a platform-specific RenderText instance.
   static RenderText* CreateNativeInstance();

ui/gfx/render_text_unittest.cc

@@ -2309,4 +2309,19 @@ TEST_F(RenderTextTest, HarfBuzz_EmptyRun) {
   EXPECT_EQ(Range(0, 0), glyphs);
 }
 
+// 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());
+  const base::string16 kString = ASCIIToUTF16("www.example.com");
+
+  render_text->SetText(kString);
+  render_text->ApplyStyle(BOLD, true, Range(0, 3));
+  render_text->SetElideBehavior(ELIDE_TAIL);
+
+  render_text->SetDisplayRect(Rect(0, 0, 500, 100));
+  EXPECT_EQ(kString, render_text->GetLayoutText());
+  render_text->SetDisplayRect(Rect(0, 0, render_text->GetContentWidth(), 100));
+  EXPECT_EQ(kString, render_text->GetLayoutText());
+}
+
 }  // namespace gfx