[Android] Implement onShowCustomView with requested orientation.

This patch is to implement the onShowCustomView function with requested
orientation.

BUG=XWALK-1868
[Android] Add test case for onShow/HideCustomView.

This patch is to add test for OnShowCustomView and onHideCustomView.
Some code was ported from android webview.
[Tizen] Remove method set_path from ApplicationData class

Method set_path from ApplicationData class is deleted.
Function in which it was called has been refactored.

BUG=XWALK-2926
[Tizen] Proof-read packaging/'s README.

Fix some typos and grammar mistakes, and mention changes to packaging/
are only included if committed unless "--include-all" is passed.
Merge pull request #2618 from rakuco/proofread-packaging-README

[Tizen] Proof-read packaging/'s README.
[Tizen] Fix allow-navigation WGT configuration element handler unit test

This patch adds unittest_util.h/cc in manifest_handlers directory, which
introduces a simple way for default W3C and WGT widget configuration creation.
[Tizen] Stop depending on nspr.

The "use_system_nspr" flag has not had any effect since February 2014
when Chromium commit 74ad623 ("Remove use_system_nspr build flag")
removed it from the build system.

Additionally, Chromium now only builds a very small subset of nspr since
commit 9af1b2e0 ("Remove prtypes.h and prcpucfg*.h from
base/third_party/nspr") so building Chromium's version should not affect
performance or cause compatibility problems.
[Tizen] packaging: Regroup conditional dependencies.

Make the list of BuildRequires and Requires easier to follow:
dependencies needed by all profiles under all configurations come first,
then the conditional dependencies are listed each in a separate block
without repeated checks.
Bump version to 11.39.246.0
[Android] Fix that trying to remote debug will cause crash

It's caused by missing a null pointer checker.

BUG=https://crosswalk-project.org/jira/browse/XWALK-2936
Merge pull request #2619 from rakuco/tizen-remove-nspr-dependency

[Tizen] Stop depending on nspr.
Merge pull request #2620 from rakuco/tizen-regroup-conditional-dependencies

[Tizen] packaging: Regroup conditional dependencies.
Merge pull request #2615 from sstolinski/sstolinski

[Tizen] Remove method set_path from ApplicationData class
Merge pull request #2617 from tweglarski/AllowNavigationUnitTestFix

[Tizen] Fix allow-navigation WGT configuration element handler unit test
Roll out M39.0.2171.62
Merge pull request #2624 from wang16/remote_debugging

[Android] Fix that trying to remote debug will cause crash
[Tizen] Add element namespace recognition in app-widget manifest handler

This patch adds code testing whether app-widget element and its children
are in tizen namespace.
Merge pull request #2625 from darktears/master

Roll out M39.0.2171.62
Bump version to 11.39.247.0
Merge pull request #2598 from wuhengzhi/show_custom_view_impl

[Android] Implement onShowCustomView and add test case.