Replace base::str[n]casecmp with helper functions.

ui/gfx/render_text_harfbuzz.cc

Index: ui/gfx/render_text_harfbuzz.cc
diff --git a/ui/gfx/render_text_harfbuzz.cc b/ui/gfx/render_text_harfbuzz.cc
index 5a3975280cc99c94798a2bff1431cc6c95e0dca4..997fe9b0bb2804e23ecbccb1df796c74f9eded1f 100644
--- a/ui/gfx/render_text_harfbuzz.cc
+++ b/ui/gfx/render_text_harfbuzz.cc
@@ -528,7 +528,7 @@ class HarfBuzzLineBreaker {
 // Function object for case insensitive string comparison.
 struct CaseInsensitiveCompare {
   bool operator() (const std::string& a, const std::string& b) const {
-    return base::strncasecmp(a.c_str(), b.c_str(), b.length()) < 0;
+    return base::CompareCaseInsensitiveASCII(a, b) < 0;
   }
 };