[Tizen][Runtime] Change to initialize access whitelist when webkit has been initialized.

After rebase to M37, in some conditions, there's no need to create javascript
context, so it's not a right place to init the access white list. This patch
will change to do it after webkit engine initialized.

BUG=XWALK-2295
[Android] Set DIP scale and refine the parameter.

This patch is to set the DIP scale in the construction of XWalkContent
and refine the parameter of onScaleChanged().
[Android] Add test case for OnScaleChanged.

This patch is to add test case for OnScaleChanged().
[Tizen] Add signature xsd file into crosswalk

Because crosswalk has replaced WRT in Tizen common image, some metadata
file which provided by wrt-installer package are missed.
signature_schema.xsd is used to verify whether signature.xml is valid.
[Tizen] Checking widget signature

Process signature file in widget according to
http://www.w3.org/TR/widgets-digsig/#signature-verification. Because
there is no Tizen CA root in image, reference validation and signature
validation on signature will be added when CA is ready.
[Android] Unregister broadcast receiver for notification properly

Unregister non-regsitered broadcast receiver will cause
crash on Android. The condition to detect whether the broadcast
receiver has been registered to receive Notification close
pending intent is change by commit eeeb8eeab.

BUG=https://crosswalk-project.org/jira/browse/XWALK-2356
Merge pull request #2291 from xuzhang/widgetsignatue

Widgetsignatue
Enable Alsa support

Bug=XWALK-2262
GetUserAgent shouldn't have Mobile for IVI

Bug = XWALK-2317
Merge pull request #2326 from wang16/notification

[Android] Unregister broadcast receiver for notification properly
Roll blink crosswalk

- [Temp] Backport r178889 from upstream
Merge pull request #2327 from darktears/master

Roll blink crosswalk
[REG] Fixed regression error that NaCl module failed to load

When rolling Chromium to version 37.0.2062.76, the interface
content::ContentMainDelegate::ZygoteStarting has been changed,
which makes it fails to call the old implementation in
xwalk::XWalkMainDelegate. Reimplemented it as indicated by chrome.

Also according to patch 1d7be68, nacl::NaClHelper is introduced
with the refactor of MessageChannel to control the in-process
and out-of-process message queue behavior, which should be created
inside xwalk::XWalkContentRendererClient::RenderFrameCreated when
NaCl is enabled.

BUG=https://crosswalk-project.org/jira/browse/XWALK-2297
Merge pull request #2322 from qjia7/alsa

Enable Alsa support
Merge pull request #2313 from qjia7/useragent

GetUserAgent shouldn't have Mobile for IVI
Revert "Enable Alsa support"
Merge pull request #2334 from crosswalk-project/revert-2322-alsa

Revert "Enable Alsa support"
Merge pull request #2332 from jondong/nacl-load-regression

[REG] Fixed regression error that NaCl module failed to load
[Android][SysApps] Add Event type for DeviceCapabilities.

Add SystemDisplayEvent and SystemStorageEvent type.

BUG=XWALK-1301
Merge pull request #2329 from legendlee1314/fixbug

[Android][SysApps] Add Event type for DeviceCapabilities.