[NavigationTiming] Working draft updated

   The working draft of the
NavigationTiming<https://dvcs.w3.org/hg/webperf/raw-file/tip/specs/NavigationTiming/Overview.html>has
been updated to address the AIs from
the last conf call. Here are the specific changes:

* * Sec. 1:  *

  For example, the following Javascript shows a naive attempt to measure the
time it takes to fully load a page:

* * Sec. 4.3*

This attribute must return the type of the last non-redirect navigation in
the current browsing context. It must have one of the following navigation
type values.

TYPE_NAVIGATE: Navigation started by clicking on a link, or entering the URL
in the user agent's address bar, or form submission, or initializing through
a script operation other than the location.reload() method.

TYPE_RELOAD: Navigation through the reload operation or the
location.reload() method.

TYPE_BACK_FORWARD: Navigation through a history traversal operation.

TYPE_RESERVED: Any navigation types not defined by values above.

  Client-side redirects, such as those using the Refresh pragma directive,
are not considered HTTP redirects or equivalent by this spec. In those
cases, the type attribute should return appropriate value, such as
TYPE_RELOAD, as if in non-redirect navigation.

 *  * Sec 4.5.3*

 Record the current navigation type in window.performance.navigation.type if
it has not been set:

   - If the navigation was started by clicking on a link, or entering the
   URL in the user agent's address bar, or form submission, or initializing
   through a script operation other than the location.reload() method, let the
   navigation type be TYPE_NAVIGATE.
   - If the navigation was started either as a result of a meta refresh, or
   the location.reload() method, or other equivalent actions, let the
   navigation type be TYPE_RELOAD.
   - If the navigation was started as a result of history traversal, let the
   navigation type be TYPE_BACK_FORWARD.
   - Otherwise, let the navigation type be TYPE_RESERVED.

  Please let me your comments.

cheers,
Zhiheng