[Android] Implement the feature about visited link.

This patch is to implement the feature about visited link.
"a:visited" does not work when the url was clicked, so this feature
should be implemented.
Most of the code was ported from android webview.

BUG=https://crosswalk-project.org/jira/browse/XWALK-986
[Android] Remove unnecessary pak file loading for sandboxed process.

Since XWalk is ALWAYS running in single process mode, the pak file loading
for sandboxed process is never be used.

BUG=
[Tizen] [Runtime] Fix the issue that widget apps fails to install without version attribute.

It reports installation crash if a widget app doesn't contains
widget 'version' attribute in the config.xml file. The root cause is
Version::GetString() always assumes a Version instance is valid, in
other words, not an empty string.

Due to the 'version' attribute could be optional for widget app, a
solution to fix this issue is we add check in
ApplicationData::VersionString().

BUG=XWALK-1226
[Android] Use render frame to retrieve web contents for some cases.

Chromium uses render frame for some cases instead of render view. This
change tries to follow up the behaviors defined by upstream.

BUG=https://crosswalk-project.org/jira/browse/XWALK-1252
Merge pull request #1730 from yongsheng/fix1252

[Android] Use render frame to retrieve web contents.
[Tizen][Runtime] Implement widget preference attribute.

The 'preferences' attribute allows authors to manipulate a widget
storage area that is unique for the instance of a widget. It does this
by implementing the Storage interface specified in
http://www.w3.org/TR/webstorage/

Spec:
http://www.w3.org/TR/widgets-apis/#the-preferences-attribute

This CL implements the below features,
1. Web Storage functions and attributes, includes,
   length, getItem(), setItem(), removeItem(), clear().
2. 'readonly' field support for the key/value pairs.
3. Remove the widget database file when uninstallation app.
4. Load Manifest configuration when creating widget DB.
Merge pull request #1713 from shaochangbin/widget_handler_preference

[Tizen][Runtime] Implement widget preference attribute.
Merge pull request #1724 from shaochangbin/fix-bugs

[Tizen] [Runtime] Fix the issue that widget apps fails to install without version attribute.
Bump canary to version 6.
Merge pull request #1733 from darktears/bump-6

Bump canary to version 6.
Merge pull request #1722 from sqliu/pak

[Android] Remove unnecessary pak file loading for sandboxed process.
Merge pull request #1682 from wuhengzhi/visited_link_color

[Android] Implement the feature about visited link.
[Android] Fix white screen issue when load http.html with manifest.

Correct the judgment of url schemes in xwalk_content.cc.

BUG=https://crosswalk-project.org/jira/browse/XWALK-985
[Tizen][Runtime] Add "allow-navigation" handler for Tizen legacy WGT
package.

This element defines a list of URL domains that are allowed to be navigated in the Web
Application window for Tizen legacy WGT.

Please refer to
https://source.tizen.org/sites/default/files/page/tizen-2.2-wrt-core-spec.pdf
for more details.
Merge pull request #1726 from ShDavidliu/PermissionCase

[Android] Add the test cases related to wrong permissions in packaging t...
Merge pull request #1729 from takethathe/allow_navigation

[Tizen][Runtime] Add "allow-navigation" handler for Tizen legacy WGT package.
Bump version to 6.34.107.0
Merge pull request #1735 from gaochun/bug985

[Android] Fix white screen issue when load http.html with manifest.
[Android] Enable the immersive fullscreen with manifest.

The fullscreen setting in manifest doesn't work with Android 4.4,
this is because there is no way to declare immersive mode in the
manifest or window flags. This fix resolves this issue by checking
the manifest fullscreen setting via manifest parser and calling the
corresponding functions of setting the immersive fullscreen mode.
In addition, the command-line parameter of immersive fullscreen
mode is also supported for packaging tool.

BUG=https://crosswalk-project.org/jira/browse/XWALK-1200