Move a bunch of windows stuff from ui/base/win to ui/gfx/win

ui/base/text/utf16_indexing.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/base/text/utf16_indexing.h"
-
-#include "base/logging.h"
-#include "base/third_party/icu/icu_utf.h"
-
-namespace ui {
-
-bool IsValidCodePointIndex(const string16& s, size_t index) {
-  return index == 0 || index == s.length() ||
-    !(CBU16_IS_TRAIL(s[index]) && CBU16_IS_LEAD(s[index - 1]));
-}
-
-ptrdiff_t UTF16IndexToOffset(const string16& s, size_t base, size_t pos) {
-  // The indices point between UTF-16 words (range 0 to s.length() inclusive).
-  // In order to consistently handle indices that point to the middle of a
-  // surrogate pair, we count the first word in that surrogate pair and not
-  // the second. The test "s[i] is not the second half of a surrogate pair" is
-  // "IsValidCodePointIndex(s, i)".
-  DCHECK_LE(base, s.length());
-  DCHECK_LE(pos, s.length());
-  ptrdiff_t delta = 0;
-  while (base < pos)
-    delta += IsValidCodePointIndex(s, base++) ? 1 : 0;
-  while (pos < base)
-    delta -= IsValidCodePointIndex(s, pos++) ? 1 : 0;
-  return delta;
-}
-
-size_t UTF16OffsetToIndex(const string16& s, size_t base, ptrdiff_t offset) {
-  DCHECK_LE(base, s.length());
-  // As in UTF16IndexToOffset, we count the first half of a surrogate pair, not
-  // the second. When stepping from pos to pos+1 we check s[pos:pos+1] == s[pos]
-  // (Python syntax), hence pos++. When stepping from pos to pos-1 we check
-  // s[pos-1], hence --pos.
-  size_t pos = base;
-  while (offset > 0 && pos < s.length())
-    offset -= IsValidCodePointIndex(s, pos++) ? 1 : 0;
-  while (offset < 0 && pos > 0)
-    offset += IsValidCodePointIndex(s, --pos) ? 1 : 0;
-  // If offset != 0 then we ran off the edge of the string, which is a contract
-  // violation but is handled anyway (by clamping) in release for safety.
-  DCHECK_EQ(offset, 0);
-  // Since the second half of a surrogate pair has "length" zero, there is an
-  // ambiguity in the returned position. Resolve it by always returning a valid
-  // index.
-  if (!IsValidCodePointIndex(s, pos))
-    ++pos;
-  return pos;
-}
-
-}  // namespace ui