clang/win: Fix build after https://codereview.chromium.org/1525263004/

Fixes

..\..\testing/gtest/include/gtest/gtest.h(1392,16) :  error: comparison of
    integers of different signs: 'const int' and 'const unsigned long'
    [-Werror,-Wsign-compare]
  if (expected == actual) {
      ~~~~~~~~ ^  ~~~~~~
..\..\content\common\cursors\webcursor_unittest.cc(301,3) :  note: in
      instantiation of function template specialization
      'testing::internal::EqHelper<false>::Compare<int, unsigned long>' here
  EXPECT_EQ(static_cast<int>(scaleFactor * hotspotX), windowsIconInfo.xHotspot);

BUG=82385,567877,161614
TBR=bsep@chromium.org

Review URL: https://codereview.chromium.org/1537483003 .

Cr-Commit-Position: refs/heads/master@{#365812}
1 file changed