Do not show translate bar for MHTML files.

chrome/browser/translate/translate_manager.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/translate/translate_manager.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/memory/singleton.h"
 #include "base/metrics/histogram.h"
@@ skipping 314 matching lines @@
 
   // Allow disabling of translate from the command line to assist with
   // automated browser testing.
   if (CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kDisableTranslate)) {
     TranslateBrowserMetrics::ReportInitiationStatus(
         TranslateBrowserMetrics::INITIATION_STATUS_DISABLED_BY_SWITCH);
     return;
   }
 
+  // MHTML pages currently cannot be translated

[MAD, 2013/08/05 15:02:27]

Add a period (.) at the end of the sentence please.

+  // see bug: 217945

[MAD, 2013/08/05 15:02:27]

Same here. And use a Capital letter at beginning of sentence, or end previous
line with a , instead of a .

+  if (web_contents->GetContentsMimeType() == "multipart/related") {
+    TranslateBrowserMetrics::ReportInitiationStatus(
+        TranslateBrowserMetrics::INITIATION_STATUS_MIME_TYPE_IS_NOT_SUPPORTED);
+    return;
+  }
+
   // Don't translate any Chrome specific page, e.g., New Tab Page, Download,
   // History, and so on.
   GURL page_url = web_contents->GetURL();
   if (!IsTranslatableURL(page_url)) {
     TranslateBrowserMetrics::ReportInitiationStatus(
         TranslateBrowserMetrics::INITIATION_STATUS_URL_IS_NOT_SUPPORTED);
     return;
   }
 
   std::string target_lang = GetTargetLanguage(prefs);
@@ skipping 372 matching lines @@
   // so we are more aggressive about showing the shortcut to never translate.
   #if defined(OS_ANDROID)
   config.never_translate_min_count = 1;
   #else
   config.never_translate_min_count = 3;
   #endif  // defined(OS_ANDROID)
 
   config.always_translate_min_count = 3;
   return config;
 }