Drop unnecessary NodeWithIndex::m_haveIndex data member

Drop unnecessary NodeWithIndex::m_haveIndex data member

Drop unnecessary NodeWithIndex::m_haveIndex data member. Since
Node::nodeIndex() returns an unsigned integer but NodeWithIndex::m_index is
signed, we can simply set m_index to -1 until it is lazily set.

R=eseidel@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=175299

[eseidel, 2014-06-02 05:13:35]

this is trading out-of-band data for in-band data.  They both have their
advantages.  Thsi is fine, but someone more language-theoretical than I should
really make a project-wide recomendation for or against this pattern.

[eseidel, 2014-06-02 05:14:09]

https://codereview.chromium.org/311563003/diff/1/Source/core/dom/NodeWithIndex.h
File Source/core/dom/NodeWithIndex.h (right):

https://codereview.chromium.org/311563003/diff/1/Source/core/dom/NodeWithInde...
Source/core/dom/NodeWithIndex.h:39: , m_index(-1)
Why was m_index not initialized before?  I guess it didn't need to be...

[eseidel, 2014-06-02 05:14:09]

https://codereview.chromium.org/311563003/diff/1/Source/core/dom/NodeWithIndex.h
File Source/core/dom/NodeWithIndex.h (right):

https://codereview.chromium.org/311563003/diff/1/Source/core/dom/NodeWithInde...
Source/core/dom/NodeWithIndex.h:39: , m_index(-1)
Why was m_index not initialized before?  I guess it didn't need to be...

[eseidel, 2014-06-02 05:14:42]

https://codereview.chromium.org/311563003/diff/1/Source/core/dom/NodeWithIndex.h
File Source/core/dom/NodeWithIndex.h (left):

https://codereview.chromium.org/311563003/diff/1/Source/core/dom/NodeWithInde...
Source/core/dom/NodeWithIndex.h:48: m_index = m_node.nodeIndex();
Can this ever return negative?

[Jeffrey Yasskin, 2014-06-02 06:06:16]

https://codereview.chromium.org/311563003/diff/1/Source/core/dom/NodeWithIndex.h
File Source/core/dom/NodeWithIndex.h (left):

https://codereview.chromium.org/311563003/diff/1/Source/core/dom/NodeWithInde...
Source/core/dom/NodeWithIndex.h:48: m_index = m_node.nodeIndex();
On 2014/06/02 05:14:42, eseidel wrote:
> Can this ever return negative?

It would be good to ASSERT that hasIndex() after this line.

[Inactive, 2014-06-02 12:10:22]

https://codereview.chromium.org/311563003/diff/1/Source/core/dom/NodeWithIndex.h
File Source/core/dom/NodeWithIndex.h (left):

https://codereview.chromium.org/311563003/diff/1/Source/core/dom/NodeWithInde...
Source/core/dom/NodeWithIndex.h:48: m_index = m_node.nodeIndex();
On 2014/06/02 05:14:42, eseidel wrote:
> Can this ever return negative?

No it cannot, this is why my change is safe. As explained in the Changelog,
nodeIndex() returns an unsigned integer:
unsigned nodeIndex() const;

https://codereview.chromium.org/311563003/diff/1/Source/core/dom/NodeWithInde...
Source/core/dom/NodeWithIndex.h:48: m_index = m_node.nodeIndex();
On 2014/06/02 06:06:16, JeffreyYasskin (OOO til Jun23) wrote:
> On 2014/06/02 05:14:42, eseidel wrote:
> > Can this ever return negative?
> 
> It would be good to ASSERT that hasIndex() after this line.

Makes sense, will do.

https://codereview.chromium.org/311563003/diff/1/Source/core/dom/NodeWithIndex.h
File Source/core/dom/NodeWithIndex.h (right):

https://codereview.chromium.org/311563003/diff/1/Source/core/dom/NodeWithInde...
Source/core/dom/NodeWithIndex.h:39: , m_index(-1)
On 2014/06/02 05:14:10, eseidel wrote:
> Why was m_index not initialized before?  I guess it didn't need to be...

Yes, it wasn't because it did not need to be (access to m_index was always
protected by checking m_haveIndex). However, I don't believe we are trading
speed since the previous code has to initialize m_haveIndex anyway.

[Inactive, 2014-06-02 12:12:19]

https://codereview.chromium.org/311563003/diff/1/Source/core/dom/NodeWithIndex.h
File Source/core/dom/NodeWithIndex.h (left):

https://codereview.chromium.org/311563003/diff/1/Source/core/dom/NodeWithInde...
Source/core/dom/NodeWithIndex.h:48: m_index = m_node.nodeIndex();
On 2014/06/02 06:06:16, JeffreyYasskin (OOO til Jun23) wrote:
> On 2014/06/02 05:14:42, eseidel wrote:
> > Can this ever return negative?
> 
> It would be good to ASSERT that hasIndex() after this line.

Done.

[eseidel, 2014-06-02 16:40:56]

lgtm

[commit-bot: I haz the power, 2014-06-02 16:41:15]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/ch.dumez@samsung.com/311563003/20001

[commit-bot: I haz the power, 2014-06-02 17:20:09]

Change committed as 175299