Remove CaseInsensitiveCompare from string_util.h

There were a number of callers in net using this for HTTP headers. I think
these callers actually just need ASCII case-insensitive comparisons so these
were changed.

The omnibox code used this functor. I added a new omnibox-specific one which
does not have the locale issues of the old string_util one, but which still
has the UTF-16 and combining accent issues (described in great detail in
the comment for this).

The Windows installer code can't depend on ICU so it calls the Win32 function
to do case-insensitive comparisons. This should match the system comparison
for registry keys better anyway.

I also changed a caller of StartsWith to use this version. I wrote this
StartsWith call using ToLower in a previous patch, but it turns out that the
lengths of case-mapped strings do change in practice, making the offset
computations of the suyrrounding code incorrect. This new version will be
like the old version (will miss some cases of case-insensitive equality) but
will handle 0x80-0xFF properly.

BUG=24917

Review URL: https://codereview.chromium.org/1230583014

Cr-Commit-Position: refs/heads/master@{#338624}

1 files changed, 6 insertions, 2 deletions

diff --git a/chrome/installer/util/shell_util.cc b/chrome/installer/util/shell_util.cc
index 87a0d58..655d2f8 100644
--- a/chrome/installer/util/shell_util.cc
+++ b/chrome/installer/util/shell_util.cc
@@ -746,8 +746,12 @@ class RegistryEntry {
       found = key.ReadValue(name_.c_str(), &read_value) == ERROR_SUCCESS;
       if (found) {
         correct_value = read_value.size() == value_.size() &&
-            std::equal(value_.begin(), value_.end(), read_value.begin(),
-                       base::CaseInsensitiveCompare<wchar_t>());
+            ::CompareString(LOCALE_USER_DEFAULT, NORM_IGNORECASE,
+                            read_value.data(),
+                            base::saturated_cast<int>(read_value.size()),
+                            value_.data(),
+                            base::saturated_cast<int>(value_.size()))
+                == CSTR_EQUAL;
       }
     } else {
       DWORD read_value;