Do not show translate bar for MHTML files.

chrome/browser/translate/translate_manager.cc

Index: chrome/browser/translate/translate_manager.cc
diff --git a/chrome/browser/translate/translate_manager.cc b/chrome/browser/translate/translate_manager.cc
index a9979ed6cb47e6b5753a91aba73f14faf2aae3e8..5b4bbc14c6ec1d3effecf51c9f5545e5b61472db 100644
--- a/chrome/browser/translate/translate_manager.cc
+++ b/chrome/browser/translate/translate_manager.cc
@@ -101,6 +101,20 @@ bool TranslateManager::IsTranslatableURL(const GURL& url) {
   // - Chrome OS file manager extension
   // - an FTP page (as FTP pages tend to have long lists of filenames that may
   //   confuse the CLD)
+  // - an MHTML page (Chrome does not load external resources when displaying
+  //   MHTML pages, see bug 262953)
+
+  // get file extension (empty if URL does not reference a file)

[Miguel Garcia, 2013/07/22 17:42:00]

I'd move this to a method and add a unittest for it (although it is interesting
that no such method exist already, can you double check it's not the case?)

+  std::string file_name, file_extension;
+  size_t path_delim = url.path().rfind('/');
+  if (path_delim != std::string::npos) {
+    file_name = url.path().substr(path_delim+1);
+    size_t file_delim = file_name.rfind('.');
+    if (file_delim != std::string::npos) {
+      file_extension = file_name.substr(file_delim+1);
+    }
+  }
+
   return !url.is_empty() &&
          !url.SchemeIs(chrome::kChromeUIScheme) &&
          !url.SchemeIs(chrome::kChromeDevToolsScheme) &&
@@ -108,7 +122,8 @@ bool TranslateManager::IsTranslatableURL(const GURL& url) {
          !(url.SchemeIs(extensions::kExtensionScheme) &&
            url.DomainIs(kFileBrowserDomain)) &&
 #endif
-         !url.SchemeIs(chrome::kFtpScheme);
+         !url.SchemeIs(chrome::kFtpScheme) &&
+         !(file_extension == "mht" || file_extension == "mhtml");

[Miguel Garcia, 2013/07/22 17:42:00]

create constants perhaps?

 }
 
 // static