[autofill] Fill in values on a successful run of interactive autocomplete.

chrome/browser/autofill/form_structure.h

Index: chrome/browser/autofill/form_structure.h
diff --git a/chrome/browser/autofill/form_structure.h b/chrome/browser/autofill/form_structure.h
index 5f96e6c6d6240595955aa385459ecf05273f15e5..d3a0268af124e27ee56e8c0258a805b4a55898b4 100644
--- a/chrome/browser/autofill/form_structure.h
+++ b/chrome/browser/autofill/form_structure.h
@@ -145,6 +145,10 @@ class FormStructure {
 
   virtual std::string server_experiment_id() const;
 
+  // Puts the data this form structure knows about into |out_data|.
+  // |out_data->user_initiated| will always be false.

[Ilya Sherman, 2012/11/29 00:08:59]

nit: "user_initiated" -> "user_submitted"

+  void ToFormData(FormData* out_data) const;

[Evan Stade, 2012/11/28 22:45:51]

return FormData*

[Ilya Sherman, 2012/11/29 00:08:59]

Conceptually this function signature should be "FormData ToFormData() const". 
However, for efficiency's sake, Chrome code usually instead uses out-params,
i.e. "void ToFormData(FormData* result) const".

Returning an un-owned heap allocated pointer is definitely wrong, so the
signature "FormData* ToFormData() const" doesn't make sense.  The signature
"scoped_ptr<FormData> ToFormData()" makes sense, but requires an extra heap
allocation, which is otherwise unnecessary.  That's why I recommended using the
current method signature.

[Evan Stade, 2012/11/29 00:20:59]

yes, FormGroup is correct rather than FormGroup*. I don't think efficiency plays
a role here because the size of the structure is quite small. Do you have any
evidence that Chrome usually uses out params? I think out params are easier to
misuse and harder to read. They are acceptable under certain circumstances, for
example if failure is possible, if multiple values need to be output, etc. None
of those apply here though.

[Ilya Sherman, 2012/11/29 00:26:43]

Fair enough -- we're about to make another copy of this data when we send it
over IPC anyway, so a copy here isn't too bad.  I was under the impression that
Chrome code usually uses out-params based on this bit of the Chromium style
guide [1]: "After testing, it seems just as fast to return a std::[w]string by
value as by out param. So we encourage passing strings out as return values when
possible for the sake of readability."  To me that suggested that things bigger
than strings should normally be returned by out param.

[1] http://dev.chromium.org/developers/coding-style#Method_Signatures

+
   bool operator==(const FormData& form) const;
   bool operator!=(const FormData& form) const;