Pass a struct to ContainerNode::childrenChanged() instead of separate arguments

Pass a struct to ContainerNode::childrenChanged() instead of separate arguments

Pass a struct to ContainerNode::childrenChanged() instead of separate
arguments. This is more extensible this way as this virtual function has a lot
of overrides. The new struct differs from the previous arguments in that:
- childCountDelta integer is replaced by a ChildrenChangeType enumeration as
  it as always (-1: ChildRemoved, +1: ChildInserted, 0: TextChanged,
  -numberOfChildren: AllChildrenRemoved)
- changedByParser boolean is replaced by an enumeration for better readability.

This CL does not contain any functional changes to keep it small. However, this
enables us to pass more information about the node being added/removed (e.g.
was it an Element?) so that we can do less recalculations is some cases.

This is based on WebKit r154957 by antti@apple.com:
http://trac.webkit.org/changeset/154957

R=esprehn@chromium.org, eseidel@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=177347

[Inactive, 2014-07-01 14:53:01]

The CL touches a lot of files because this virtual function has a lot of
overrides. However, the changes are trivial / mechanical (expect for the one I
commented on).

https://codereview.chromium.org/365673002/diff/20001/Source/core/html/HTMLEle...
File Source/core/html/HTMLElement.cpp (left):

https://codereview.chromium.org/365673002/diff/20001/Source/core/html/HTMLEle...
Source/core/html/HTMLElement.cpp:763: for (int counter = 0; node && counter <
childCountDelta; counter++, node = NodeTraversal::nextSkippingChildren(*node)) {
This was dead code because:
- if childCountDelta < 0
- and counter is initialized to 0 (then incremented)
-> then (counter < childCountDelta) can _never_ be true

[eseidel, 2014-07-01 23:47:50]

lgtm

Much nicer.

[commit-bot: I haz the power, 2014-07-01 23:48:57]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/ch.dumez@samsung.com/365673002/20001

[commit-bot: I haz the power, 2014-07-02 00:10:23]

Change committed as 177347