Fix Autofill hang when interacting with large forms (i.e. forms containing many fields).

chrome/renderer/autofill/form_autofill_util.h

 // Copyright (c) 2011 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.
 
 #ifndef CHROME_RENDERER_AUTOFILL_FORM_AUTOFILL_UTIL_H_
 #define CHROME_RENDERER_AUTOFILL_FORM_AUTOFILL_UTIL_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 26 matching lines @@
   EXTRACT_VALUE       = 1 << 0,  // Extract value from WebFormControlElement.
   EXTRACT_OPTION_TEXT = 1 << 1,  // Extract option text from
                                  // WebFormSelectElement. Only valid when
                                  // |EXTRACT_VALUE| is set.
                                  // This is used for form submission where
                                  // human readable value is captured.
   EXTRACT_OPTIONS     = 1 << 2,  // Extract options from
                                  // WebFormControlElement.
 };
 
+// The maximum number of form fields we are willing to parse, due to
+// computational costs.  Several examples of forms with lots of fields that are
+// not relevant to Autofill: (1) the Netflix queue; (2) the Amazon wishlist;
+// (3) router configuration pages; and (4) other configuration pages, e.g. for
+// Google code project settings.
+extern const size_t kMaxParseableFields;
+
 // Returns true if |element| is a text input element.
 bool IsTextInput(const WebKit::WebInputElement* element);
 
 // Returns true if |element| is a select element.
 bool IsSelectElement(const WebKit::WebFormControlElement& element);
 
 // Returns the form's |name| attribute if non-empty; otherwise the form's |id|
 // attribute.
 const string16 GetFormIdentifier(const WebKit::WebFormElement& form);
 
 // Fills |autofillable_elements| with all the auto-fillable form control
 // elements in |form_element|.
 void ExtractAutofillableElements(
     const WebKit::WebFormElement& form_element,
     RequirementsMask requirements,
     std::vector<WebKit::WebFormControlElement>* autofillable_elements);
 
 // Fills out a FormField object from a given WebFormControlElement.
 // |extract_mask|: See the enum ExtractMask above for details.
 void WebFormControlElementToFormField(
     const WebKit::WebFormControlElement& element,
     ExtractMask extract_mask,
     webkit::forms::FormField* field);
 
 // Fills |form| with the FormData object corresponding to the |form_element|.
 // If |field| is non-NULL, also fills |field| with the FormField object
 // corresponding to the |form_control_element|.
 // |extract_mask| controls what data is extracted.
 // Returns true if |form| is filled out; it's possible that the |form_element|
-// won't meet the |requirements|.  Also returns false if there are no fields
-// in the |form|.
+// won't meet the |requirements|.  Also returns false if there are no fields or
+// too many fields in the |form|.
 bool WebFormElementToFormData(
     const WebKit::WebFormElement& form_element,
     const WebKit::WebFormControlElement& form_control_element,
     RequirementsMask requirements,
     ExtractMask extract_mask,
     webkit::forms::FormData* form,
     webkit::forms::FormField* field);
 
 // Finds the form that contains |element| and returns it in |form|.  Fills
 // |field| with the |FormField| representation for element.
-// Returns false if the form is not found.
+// Returns false if the form is not found or cannot be serialized.
 bool FindFormAndFieldForInputElement(const WebKit::WebInputElement& element,
                                      webkit::forms::FormData* form,
                                      webkit::forms::FormField* field,
                                      RequirementsMask requirements);
 
 // Fills the form represented by |form|.  |element| is the input element that
 // initiated the auto-fill process.
 void FillForm(const webkit::forms::FormData& form,
               const WebKit::WebInputElement& element);
 
 // Previews the form represented by |form|.  |element| is the input element that
 // initiated the preview process.
 void PreviewForm(const webkit::forms::FormData& form,
                  const WebKit::WebInputElement& element);
 
 // Clears the placeholder values and the auto-filled background for any fields
 // in the form containing |node| that have been previewed.  Resets the
 // autofilled state of |node| to |was_autofilled|.  Returns false if the form is
 // not found.
 bool ClearPreviewedFormWithElement(const WebKit::WebInputElement& element,
                                    bool was_autofilled);
 
 // Returns true if |form| has any auto-filled fields.
 bool FormWithElementIsAutofilled(const WebKit::WebInputElement& element);
 
 }  // namespace autofill
 
 #endif  // CHROME_RENDERER_AUTOFILL_FORM_AUTOFILL_UTIL_H_