Create untrusted offline page for content URL with message/rfc822 type

Bug: 831831
Change-Id: If1a36fbec7e73571d7d8c6a921afb3d8fa9b70c3
Reviewed-on: https://chromium-review.googlesource.com/1008635Reviewed-by: Yafei Duan <romax@chromium.org>
Commit-Queue: Jian Li <jianli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549998}

chrome/browser/offline_pages/offline_page_tab_helper.cc

@@ -175,8 +175,10 @@ void OfflinePageTabHelper::FinalizeOfflineInfo(
   GURL navigated_url = navigation_handle->GetURL();
 
   content::WebContents* web_contents = navigation_handle->GetWebContents();
-  if (web_contents->GetContentsMimeType() != "multipart/related")
+  if (web_contents->GetContentsMimeType() != "multipart/related" &&
+      web_contents->GetContentsMimeType() != "message/rfc822") {
     return;
+  }
 
   if (SchemeIsForUntrustedOfflinePages(navigated_url)) {
     // If a MHTML archive is being loaded for file: or content: URL, and we did

chrome/browser/offline_pages/offline_page_tab_helper_unittest.cc

@@ -239,7 +239,8 @@ TEST_F(OfflinePageTabHelperTest, UntrustedOfflinePageForFileUrl) {
 }
 
 #if defined(OS_ANDROID)
-TEST_F(OfflinePageTabHelperTest, UntrustedOfflinePageForContentUrl) {
+TEST_F(OfflinePageTabHelperTest,
+       UntrustedOfflinePageForContentUrlWithMultipartRelatedType) {
   CreateNavigationSimulator(kTestContentUrl);
   navigation_simulator()->Start();
   navigation_simulator()->SetContentsMimeType("multipart/related");
@@ -251,6 +252,20 @@ TEST_F(OfflinePageTabHelperTest, UntrustedOfflinePageForContentUrl) {
   EXPECT_EQ(OfflinePageHeader::Reason::NONE,
             tab_helper()->offline_header().reason);
 }
+
+TEST_F(OfflinePageTabHelperTest,
+       UntrustedOfflinePageForContentUrlWithMessageRfc822Type) {
+  CreateNavigationSimulator(kTestContentUrl);
+  navigation_simulator()->Start();
+  navigation_simulator()->SetContentsMimeType("message/rfc822");
+  navigation_simulator()->Commit();
+
+  ASSERT_NE(nullptr, tab_helper()->offline_page());
+  EXPECT_EQ(OfflinePageTrustedState::UNTRUSTED, tab_helper()->trusted_state());
+  EXPECT_FALSE(tab_helper()->IsShowingTrustedOfflinePage());
+  EXPECT_EQ(OfflinePageHeader::Reason::NONE,
+            tab_helper()->offline_header().reason);
+}
 #endif
 
 TEST_F(OfflinePageTabHelperTest, TestNotifyIsMhtmlPage) {