MHTML generation: safely serialize image documents

third_party/WebKit/Source/web/tests/WebFrameSerializerTest.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 180 matching lines @@
   EXPECT_EQ("<!-- saved from url=(0030)http://www.test.com/?-%2Dx-%2D -->",
             actualHTML.substring(1, 60));
 }
 
 class WebFrameSerializerSanitizationTest : public WebFrameSerializerTest {
  protected:
   WebFrameSerializerSanitizationTest() {}
 
   ~WebFrameSerializerSanitizationTest() override {}
 
-  String generateMHTMLParts(const String& url, const String& fileName) {
+  String generateMHTMLParts(const String& url,
+                            const String& fileName,
+                            const String& mimeType = "text/html") {
     KURL parsedURL(ParsedURLString, url);
     URLTestHelpers::registerMockedURLLoad(parsedURL, fileName,
-                                          "frameserialization/", "text/html");
+                                          "frameserialization/", mimeType);
     FrameTestHelpers::loadFrame(mainFrameImpl(), url.utf8().data());
     WebThreadSafeData result = WebFrameSerializer::generateMHTMLParts(
         WebString("boundary"), mainFrameImpl(), &m_mhtmlDelegate);
     return String(result.data(), result.size());
   }
 
  private:
   SimpleMHTMLPartsGenerationDelegate m_mhtmlDelegate;
 };
 
@@ skipping 52 matching lines @@
   EXPECT_NE(WTF::kNotFound, mhtml.find("<h2"));
 
   // These visible elements should remain intact.
   EXPECT_NE(WTF::kNotFound, mhtml.find("<h2"));
   EXPECT_NE(WTF::kNotFound, mhtml.find("<p id=3D\"visible_id\""));
   EXPECT_NE(WTF::kNotFound, mhtml.find("<form"));
   EXPECT_NE(WTF::kNotFound, mhtml.find("<input type=3D\"text\""));
   EXPECT_NE(WTF::kNotFound, mhtml.find("<div"));
 }
 
+// Regression test for crbug.com/678893, where in some cases serializing an
+// image document could cause code to pick an element from an empty container.
+TEST_F(WebFrameSerializerSanitizationTest, FromBrokenImageDocument) {
+  String mhtml = generateMHTMLParts("http://www.test.com", "broken-image.png",
+                                    "image/png");
+  EXPECT_TRUE(mhtml.isEmpty());
+}
+
 }  // namespace blink