[Android] File picker can't work on Android OS

This is a regression issue when chromium-crosswalk rebased to 34.
In Chromium 34, showCancelableIntent function is implemented in ActivityWindowAndroid.
When context is a Activity, we need a ActivityWindowAndroid instance instead of
WindowAndroid.

BUG=https://crosswalk-project.org/jira/browse/XWALK-1086
[Android][Extension] Fix that crosswalk crashes by can't create jni local ref

It's caused by android extension never release the jstring as
the message posted to Java side.

Fixed it by using ScopedJavaLocalRef for the jstring.

BUG=XWALK-1189
Merge pull request #1701 from takethathe/wgt_csp_handler

[Tizen][Runtime] Enable WGT CSP support.
Merge pull request #1700 from wang16/ext_local_ref

[Android][Extension] Fix that crosswalk crashes by can't create jni loca...
Merge pull request #1691 from yinli/file_picker

[Android] File picker can't work on Android OS
Bump version to 5.34.99.0
[Runtime] Use Manifest::HasPath() method instead of the
Manifest::HasKey().

Since the Manifest::HasKey() method is looking for the key under current
ValueDirectory object, this is not compatible with WGT manifest file
structure, so change it to Manifest::HasPath().

Fix one coding style issue.