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

net/base/mime_util.cc

Index: net/base/mime_util.cc
diff --git a/net/base/mime_util.cc b/net/base/mime_util.cc
index 0a1774261ad45f5ba024842871cc747a2ed8e386..6bc825f5dbee7ffae79bab40e4ff5a87bf306545 100644
--- a/net/base/mime_util.cc
+++ b/net/base/mime_util.cc
@@ -116,7 +116,8 @@ const char* FindMimeType(const MimeInfo* mappings,
     for (;;) {
       size_t end_pos = strcspn(extensions, ",");
       if (end_pos == ext.size() &&

[Nico, 2015/07/08 21:58:23]

I was about to say that EqualsCase...() already does an early check for size, so
you could delete this, but it's actually required to make the StringPiece()
below not point at uninitialized memory if ext is long. A bit subtle.

[brettw, 2015/07/08 22:35:17]

Yeah, I added a comment for clarity.

-          base::strncasecmp(extensions, ext.data(), ext.size()) == 0)
+          base::EqualsCaseInsensitiveASCII(
+              base::StringPiece(extensions, ext.size()), ext))
         return mappings[i].mime_type;
       extensions += end_pos;
       if (!*extensions)
@@ -267,13 +268,10 @@ bool MimeUtil::MatchesMimeType(const std::string& mime_type_pattern,
 
   const std::string::size_type star = base_pattern.find('*');
   if (star == std::string::npos) {
-    if (base_pattern.size() == base_type.size() &&
-        base::strncasecmp(base_pattern.data(), base_type.data(),
-                          base_pattern.size()) == 0) {
+    if (base::EqualsCaseInsensitiveASCII(base_pattern, base_type))
       return MatchesMimeTypeParameters(mime_type_pattern, mime_type);
-    } else {
+    else
       return false;
-    }
   }
 
   // Test length to prevent overlap between |left| and |right|.