Remove hidden elements from MHTML

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 57 matching lines @@
 
   WebString getContentID(WebFrame*) final { return WebString("<cid>"); }
 
   WebFrameSerializerCacheControlPolicy cacheControlPolicy() final {
     return WebFrameSerializerCacheControlPolicy::None;
   }
 
   bool useBinaryEncoding() final { return false; }
 };
 
+// Returns the count of match for substring |pattern| in string |str|.
+int matchSubstring(const String& str, const char* pattern, size_t size) {
+  int matches = 0;
+  size_t start = 0;
+  while (true) {
+    size_t pos = str.find(pattern, start);
+    if (pos == WTF::kNotFound)
+      break;
+    matches++;
+    start = pos + size;
+  }
+  return matches;
+}
+
 }  // namespace
 
 class WebFrameSerializerTest : public testing::Test {
  protected:
   WebFrameSerializerTest() { m_helper.initialize(); }
 
   ~WebFrameSerializerTest() override {
     Platform::current()->getURLLoaderMockFactory()->unregisterAllURLs();
     WebCache::clear();
   }
@@ skipping 128 matching lines @@
   EXPECT_NE(WTF::kNotFound, mhtml.find("id="));
 
   // srcdoc attribute of frame element should be replaced with src attribute.
   EXPECT_EQ(WTF::kNotFound, mhtml.find("srcdoc="));
   EXPECT_NE(WTF::kNotFound, mhtml.find("src="));
 }
 
 TEST_F(WebFrameSerializerSanitizationTest, DisableFormElements) {
   String mhtml = generateMHTMLParts("http://www.test.com", "form.html");
 
-  int matches = 0;
-  size_t start = 0;
-  while (true) {
-    const char kDisabledAttr[] = "disabled=3D\"\"";
-    size_t pos = mhtml.find(kDisabledAttr, start);
-    if (pos == WTF::kNotFound)
-      break;
-    matches++;
-    start = pos + arraysize(kDisabledAttr) - 1;
-  }
+  const char kDisabledAttr[] = "disabled=3D\"\"";
+  int matches =
+      matchSubstring(mhtml, kDisabledAttr, arraysize(kDisabledAttr) - 1);
   EXPECT_EQ(21, matches);
 }
 
+TEST_F(WebFrameSerializerSanitizationTest, RemoveHiddenElements) {
+  String mhtml =
+      generateMHTMLParts("http://www.test.com", "hidden_elements.html");
+
+  // These hidden elements that do not affect layout should be removed.
+  EXPECT_EQ(WTF::kNotFound, mhtml.find("<h1"));
+  EXPECT_EQ(WTF::kNotFound, mhtml.find("<p id=3D\"hidden_id\""));
+  EXPECT_EQ(WTF::kNotFound, mhtml.find("<input type=3D\"hidden\""));
+
+  // These default-hidden elements should not be removed.
+  EXPECT_NE(WTF::kNotFound, mhtml.find("<html"));
+  EXPECT_NE(WTF::kNotFound, mhtml.find("<head"));
+  EXPECT_NE(WTF::kNotFound, mhtml.find("<style"));
+  EXPECT_NE(WTF::kNotFound, mhtml.find("<title"));
+  EXPECT_NE(WTF::kNotFound, mhtml.find("<link"));
+  EXPECT_NE(WTF::kNotFound, mhtml.find("<datalist"));
+  EXPECT_NE(WTF::kNotFound, mhtml.find("<option"));
+  // One for meta in head and another for meta in body.
+  EXPECT_EQ(2, matchSubstring(mhtml, "<meta", 5));
+
+  // These hidden elements that affect layout should remain intact.
+  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"));
+}
+
 }  // namespace blink