Fix infinite loop caused by ElideText()

ui/base/text/text_elider_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.
 //
 // Unit tests for eliding and formatting utility functions.
 
 #include "ui/base/text/text_elider.h"
 
 #include "base/files/file_path.h"
 #include "base/i18n/rtl.h"
@@ skipping 327 matching lines @@
     { "Tests", kTestWidth, "Test" },
   };
 
   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(cases); ++i) {
     string16 result = ElideText(UTF8ToUTF16(cases[i].input), font,
                                 cases[i].width, TRUNCATE_AT_END);
     EXPECT_EQ(cases[i].output, UTF16ToUTF8(result));
   }
 }
 
+TEST(TextEliderTest, ElideTextEllipsis) {
+  const gfx::Font font;
+  const int kTestWidth = font.GetStringWidth(ASCIIToUTF16("Test"));
+  const char* kEllipsis = "\xE2\x80\xA6";
+  const int kEllipsisWidth = font.GetStringWidth(UTF8ToUTF16(kEllipsis));
+  struct TestData {
+    const char* input;
+    int width;
+    const char* output;
+  } cases[] = {
+    { "", 0, "" },
+    { "Test", 0, "" },
+    { "Test", kEllipsisWidth, kEllipsis },
+    { "", kTestWidth, "" },
+    { "Tes", kTestWidth, "Tes" },
+    { "Test", kTestWidth, "Test" },
+  };
+
+  for (size_t i = 0; i < ARRAYSIZE_UNSAFE(cases); ++i) {
+    string16 result = ElideText(UTF8ToUTF16(cases[i].input), font,
+                                cases[i].width, ELIDE_AT_END);
+    EXPECT_EQ(cases[i].output, UTF16ToUTF8(result));
+  }
+}
+
 // Checks that all occurrences of |first_char| are followed by |second_char| and
 // all occurrences of |second_char| are preceded by |first_char| in |text|.
 static void CheckSurrogatePairs(const string16& text,
                                 char16 first_char,
                                 char16 second_char) {
   size_t index = text.find_first_of(first_char);
   while (index != string16::npos) {
     EXPECT_LT(index, text.length() - 1);
     EXPECT_EQ(second_char, text[index + 1]);
     index = text.find_first_of(first_char, index + 1);
@@ skipping 542 matching lines @@
 
   // Test adds ... at right spot when there is not enough room to break at a
   // word boundary.
   EXPECT_EQ(L"foooooey\x2026", UTF16ToWide(TruncateString(string, 11)));
 
   // Test completely truncates string if break is on initial whitespace.
   EXPECT_EQ(L"\x2026", UTF16ToWide(TruncateString(ASCIIToUTF16("   "), 2)));
 }
 
 }  // namespace ui