Promoting the MHTML file extension to primary mappings.

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 1ff023db24ee1e8d201374635aa2a02fc56f707c..6c5035455b4515123cd6cadb149b2e7c6047d7bb 100644
--- a/net/base/mime_util.cc
+++ b/net/base/mime_util.cc
@@ -95,7 +95,8 @@ static const MimeInfo primary_mappings[] = {
   { "audio/webm", "webm" },
   { "audio/wav", "wav" },
   { "application/xhtml+xml", "xhtml,xht" },
-  { "application/x-chrome-extension", "crx" }
+  { "application/x-chrome-extension", "crx" },
+  { "multipart/related", "mhtml,mht" }
 };
 
 static const MimeInfo secondary_mappings[] = {
@@ -117,8 +118,7 @@ static const MimeInfo secondary_mappings[] = {
   { "application/rdf+xml", "rdf" },
   { "text/xml", "xsl,xbl" },
   { "application/vnd.mozilla.xul+xml", "xul" },
-  { "application/x-shockwave-flash", "swf,swl" },
-  { "multipart/related", "mht,mhtml" }
+  { "application/x-shockwave-flash", "swf,swl" }
 };
 
 static const char* FindMimeType(const MimeInfo* mappings,