Merge ObjectIterator::has_next and ObjectIterator::next methods....

Merge ObjectIterator::has_next and ObjectIterator::next methods.

This reduces chances of improper usage, see http://code.google.com/p/v8/issues/detail?id=586
for more details.

BUG=586
Committed: http://code.google.com/p/v8/source/detail?r=3696

[antonm, 2010-01-25 10:17:12]

Just FYI.  I tried to unify PageIterator, but there are couple of places where
has_next is used to determine if that's the last page.

And actually I placed two unnecessary .has_next's before when iterating by
PageIterator, they are removed now.

[Søren Thygesen Gjesse, 2010-01-25 13:01:40]

LGTM with a style comment:

In the V8 code base we always have explicit check against NULL, so

  while (HeapObject* obj = it.next()) {

needs to be 

  while ((HeapObject* obj = it.next()) != NULL) {

[Søren Thygesen Gjesse, 2010-01-25 13:39:20]

On 2010/01/25 13:01:40, Søren Gjesse wrote:
> LGTM with a style comment:
> 
> In the V8 code base we always have explicit check against NULL, so
> 
>   while (HeapObject* obj = it.next()) {
> 
> needs to be 
> 
>   while ((HeapObject* obj = it.next()) != NULL) {

As the while with != NULL check requires hoisting the declaration of obj out of
the while scope using a for loop

  for (HeapObject* obj = it.next(); obj != NULL; obj = it.next()) {

is probably the best choice.