SavePackageFilePickerChromeOS should only force MHTML when saving HTML, not when saving text/image/…

content/browser/download/save_package.cc

Index: content/browser/download/save_package.cc
diff --git a/content/browser/download/save_package.cc b/content/browser/download/save_package.cc
index bff3a1ad70561a64c19238de54b70503f6b095c6..6125ea571b81cd36b482f5840a6fe99346f19d22 100644
--- a/content/browser/download/save_package.cc
+++ b/content/browser/download/save_package.cc
@@ -305,6 +305,7 @@ bool SavePackage::Init(
     web_contents()->GenerateMHTML(saved_main_file_path_, base::Bind(
         &SavePackage::OnMHTMLGenerated, this));
   } else {
+    DCHECK_EQ(SAVE_PAGE_TYPE_AS_ONLY_HTML, save_type_) << save_type_;
     wait_state_ = NET_FILES;
     SaveFileCreateInfo::SaveFileSource save_source = page_url_.SchemeIsFile() ?
         SaveFileCreateInfo::SAVE_FILE_FROM_FILE :
@@ -1361,6 +1362,9 @@ void SavePackage::OnPathPicked(
     const base::FilePath& final_name,
     SavePageType type,
     const SavePackageDownloadCreatedCallback& download_created_callback) {
+  DCHECK((type == SAVE_PAGE_TYPE_AS_ONLY_HTML) ||
+         (type == SAVE_PAGE_TYPE_AS_MHTML) ||
+         (type == SAVE_PAGE_TYPE_AS_COMPLETE_HTML)) << type;
   // Ensure the filename is safe.
   saved_main_file_path_ = final_name;
   // TODO(asanka): This call may block on IO and shouldn't be made