Reland: [ios] Refactored back-forward navigation in CRWSessionController.

Reland: [ios] Refactored back-forward navigation in CRWSessionController.

Notable changes:
 - Added public -[CRWSessionController indexOfEntryForDelta:] which will
   be used in future BF navigation refactorings (crbug.com/661858). This
   API will allow to tell the future navigation index w/o making an
   actual navigation and pass that future entry to
   |isSameDocumentNavigationBetweenEntry:andEntry:| call.
 - Made goDelta: no-op if delta is out of bounds. This make
   CRWSessionController  implementation better conform to w3 spec:
   https://www.w3.org/TR/html5/browsers.html#the-history-interface
 - Added public canGoDelta: API and use it in canGoBack/canGoForward.
 - goBack and goForward now implemented by calling goDelta:-1 and
   goDelta:1. This way the implementation is more efficient (no extra
   calls of |discardNonCommittedEntries| and |discardTransientEntry|)
   and cleaner.
 - Do not change previousNavigationIndex if navigation did not happen.
 - Added more unit tests.

Further cleanups (like reusing indexOfEntryForDelta: and
isRedirectTransitionForEntryAtIndex:) will be done in separate CLs.

BUG=661820
Review-Url: https://codereview.chromium.org/2470913007
Cr-Commit-Position: refs/heads/master@{#430435}
(cherry picked from commit 44dc0832429cf6754c254739d4939382e5ee3b71)

Committed: https://crrev.com/56ef246026d69de2002f0068c64fb54000207bce
Cr-Commit-Position: refs/heads/master@{#430672}

[Eugene But (OOO till 7-30), 2016-11-08 04:03:01]

eugenebut@chromium.org changed reviewers:
+ kkhorimoto@chromium.org

[Eugene But (OOO till 7-30), 2016-11-08 04:03:01]

https://codereview.chromium.org/2482983003/diff/20001/ios/web/navigation/crw_...
File ios/web/navigation/crw_session_controller.mm (right):

https://codereview.chromium.org/2482983003/diff/20001/ios/web/navigation/crw_...
ios/web/navigation/crw_session_controller.mm:887: return (transition &
ui::PAGE_TRANSITION_IS_REDIRECT_MASK) ? YES : NO;
https://google.github.io/styleguide/objcguide.xml#BOOL_Pitfalls

[kkhorimoto, 2016-11-08 18:19:21]

lgtm

[Eugene But (OOO till 7-30), 2016-11-08 18:37:03]

The CQ bit was checked by eugenebut@chromium.org

[commit-bot: I haz the power, 2016-11-08 18:37:40]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-08 18:47:59]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-11-08 19:08:41]

Description was changed from

==========
Reland: [ios] Refactored back-forward navigation in CRWSessionController.

Notable changes:
 - Added public -[CRWSessionController indexOfEntryForDelta:] which will
   be used in future BF navigation refactorings (crbug.com/661858). This
   API will allow to tell the future navigation index w/o making an
   actual navigation and pass that future entry to
   |isSameDocumentNavigationBetweenEntry:andEntry:| call.
 - Made goDelta: no-op if delta is out of bounds. This make
   CRWSessionController  implementation better conform to w3 spec:
   https://www.w3.org/TR/html5/browsers.html#the-history-interface
 - Added public canGoDelta: API and use it in canGoBack/canGoForward.
 - goBack and goForward now implemented by calling goDelta:-1 and
   goDelta:1. This way the implementation is more efficient (no extra
   calls of |discardNonCommittedEntries| and |discardTransientEntry|)
   and cleaner.
 - Do not change previousNavigationIndex if navigation did not happen.
 - Added more unit tests.

Further cleanups (like reusing indexOfEntryForDelta: and
isRedirectTransitionForEntryAtIndex:) will be done in separate CLs.

BUG=661820

Review-Url: https://codereview.chromium.org/2470913007
Cr-Commit-Position: refs/heads/master@{#430435}
(cherry picked from commit 44dc0832429cf6754c254739d4939382e5ee3b71)
==========

to

==========
Reland: [ios] Refactored back-forward navigation in CRWSessionController.

Notable changes:
 - Added public -[CRWSessionController indexOfEntryForDelta:] which will
   be used in future BF navigation refactorings (crbug.com/661858). This
   API will allow to tell the future navigation index w/o making an
   actual navigation and pass that future entry to
   |isSameDocumentNavigationBetweenEntry:andEntry:| call.
 - Made goDelta: no-op if delta is out of bounds. This make
   CRWSessionController  implementation better conform to w3 spec:
   https://www.w3.org/TR/html5/browsers.html#the-history-interface
 - Added public canGoDelta: API and use it in canGoBack/canGoForward.
 - goBack and goForward now implemented by calling goDelta:-1 and
   goDelta:1. This way the implementation is more efficient (no extra
   calls of |discardNonCommittedEntries| and |discardTransientEntry|)
   and cleaner.
 - Do not change previousNavigationIndex if navigation did not happen.
 - Added more unit tests.

Further cleanups (like reusing indexOfEntryForDelta: and
isRedirectTransitionForEntryAtIndex:) will be done in separate CLs.

BUG=661820

Review-Url: https://codereview.chromium.org/2470913007
Cr-Commit-Position: refs/heads/master@{#430435}
(cherry picked from commit 44dc0832429cf6754c254739d4939382e5ee3b71)

Committed: https://crrev.com/56ef246026d69de2002f0068c64fb54000207bce
Cr-Commit-Position: refs/heads/master@{#430672}
==========

[commit-bot: I haz the power, 2016-11-08 19:08:42]

Patchset 2 (id:??) landed as
https://crrev.com/56ef246026d69de2002f0068c64fb54000207bce
Cr-Commit-Position: refs/heads/master@{#430672}