Autofill's "Clear Form" should clear only autofilled fields

components/autofill/content/renderer/form_cache.cc

 // Copyright 2013 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 "components/autofill/content/renderer/form_cache.h"
 
 #include "base/logging.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/autofill/content/renderer/form_autofill_util.h"
 #include "components/autofill/core/common/autofill_constants.h"
@@ skipping 159 matching lines @@
 
   std::vector<WebFormControlElement> control_elements;
   ExtractAutofillableElements(form_element, autofill::REQUIRE_NONE,
                               &control_elements);
   for (size_t i = 0; i < control_elements.size(); ++i) {
     WebFormControlElement control_element = control_elements[i];
     // Don't modify the value of disabled fields.
     if (!control_element.isEnabled())
       continue;
 
+    // Don't clear field that was not autofilled
+    if (!control_element.isAutofilled())
+      continue;
+
     control_element.setAutofilled(false);
 
     WebInputElement* input_element = toWebInputElement(&control_element);
     if (IsTextInput(input_element) || IsMonthInput(input_element)) {
       input_element->setValue(base::string16(), true);
 
       // Clearing the value in the focused node (above) can cause selection
       // to be lost. We force selection range to restore the text cursor.
       if (element == *input_element) {
         int length = input_element->value().length();
@@ skipping 90 matching lines @@
       element->setAttribute("placeholder",
                             WebString(base::UTF8ToUTF16(placeholder)));
     }
     element->setAttribute("title", WebString(title));
   }
 
   return true;
 }
 
 }  // namespace autofill