[Android] Fix the access issues from iframe.

This patch is to fix the cross origin issues when access the different
origin urls in iframe.
The instance of XWalkSettings was not initialized when the preference
value was got, so can not set the value to XWalkSettings.
Adjust the code to generate the instance of XWalkSettings before load
the preference value.

BUG=XWALK-2685, XWALK-2905
Merge pull request #2657 from wuhengzhi/xwalk_2685_2905_iframe_access_issue

[Android] Fix the access issues from iframe.
The xwalk::Runtime class (and related code) refactoring

The major changes (improvements):
- The Runtime class now only handles WebContents, it's unaware of the UI.
- The Runtime UI logic is encapsulated within the RuntimeUIDelegate implementation.
- Runtime life-cycle is definite - it is owned by the observer instead of being a suicide.
- Runtime::Close() causes the wrapped content::WebContents::Close() which had not happen(!) before.
- Multiple code clean-ups and simplification.
Merge pull request #2630 from pozdnyakov/runtime_refactoring

 The xwalk::Runtime class (and related code) refactoring
Bump version to 11.39.254.0
[Tizen] Enable/Disable the shared process mode at runtime.

The shared process mode has been enabled by default, which makes
debugging very hard so we need to enable/disable it at runtime.

This patch allows to add a new command line option
(--disable-shared-process-mode) for disabling the shared process
mode at runtime.

Bug=XWALK-2987