[Android] Fix virtual Override in ClientMapEntryUpdater

Base class doesn't have any parameter.
[Android] Rename version to xwalk_version in manifest and make it optional

According W3C manifest spec, 'version' field of manifest should be:
1) renamed to "xwalk_version"
2) optional
3) the "version" field should be handled if present, but issue a deprecation warning

BUG=https://crosswalk-project.org/jira/browse/XWALK-2053
Update codebase to use scoped_refptr<T>::get() rather
than implicit "operator T*"

It's going to be removed upstream at some point
http://code.google.com/p/chromium/issues/detail?id=110610
Merge pull request #2244 from darktears/scoped

Update codebase to use scoped_refptr<T>::get() rather
Merge pull request #2197 from PeterWangIntel/PR2053

[Android] "version" field in manifest should not be mandatory and should...
Merge pull request #2243 from darktears/fix-client-map-android

[Android] Fix virtual Override in ClientMapEntryUpdater