[Autofill] Fill fields if they contain a default value.

components/autofill/content/renderer/form_autofill_util.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_autofill_util.h"
 
 #include <map>
 #include <set>
 
 #include "base/command_line.h"
@@ skipping 787 matching lines @@
       // rename form fields while the user is interacting with the Autofill
       // popup.  I (isherman) am not aware of any such websites, and so am
       // optimistically including a NOTREACHED().  If you ever trip this check,
       // please file a bug against me.
       NOTREACHED();
       continue;
     }
 
     bool is_initiating_element = (*element == initiating_element);
 
-    // Only autofill empty fields and the field that initiated the filling,
-    // i.e. the field the user is currently editing and interacting with.
+    // Only autofill empty fields (or those with the field's default value
+    // attribute) and the field that initiated the filling, i.e. the field the
+    // user is currently editing and interacting with.
     const WebInputElement* input_element = toWebInputElement(element);
+    CR_DEFINE_STATIC_LOCAL(WebString, kValue, ("value"));
     if (!force_override && !is_initiating_element &&
-        ((IsAutofillableInputElement(input_element) ||
-          IsTextAreaElement(*element)) &&
-         !element->value().isEmpty()))
+        // A text field, with a non-empty value that is NOT the value of the
+        // input field's "value" attribute, is skipped.
+        (IsAutofillableInputElement(input_element) ||
+         IsTextAreaElement(*element)) &&
+        !element->value().isEmpty() &&
+        (!element->hasAttribute(kValue) ||
+         element->getAttribute(kValue) != element->value()))
       continue;
 
     if (((filters & FILTER_DISABLED_ELEMENTS) && !element->isEnabled()) ||
         ((filters & FILTER_READONLY_ELEMENTS) && element->isReadOnly()) ||
         // See description for FILTER_NON_FOCUSABLE_ELEMENTS.
         ((filters & FILTER_NON_FOCUSABLE_ELEMENTS) && !element->isFocusable() &&
          !IsSelectElement(*element)))
       continue;
 
     callback(data.fields[i], is_initiating_element, element);
@@ skipping 926 matching lines @@
     // Zero selection start is for password manager, which can show usernames
     // that do not begin with the user input value.
     selection_start = (offset == base::string16::npos) ? 0 : offset;
   }
 
   input_element->setSelectionRange(selection_start, suggestion.length());
 }
 
 }  // namespace form_util
 }  // namespace autofill