Reset CordovaBridge correctly on navigation.

If the bridge is reset incorrectly, its loadedUrl remains null, which
causes a NullPointerException when a non-file:// page tries to connect
to the bridge via prompt().

Relevant upstream code:
https://github.com/apache/cordova-android/blob/master/framework/src/org/apache/cordova/CordovaWebViewClient.java#L144

BUG=XWALK-2907

(cherry picked from commit 88a9e71d3262579f859344ff8172ffb882608b70)
Reset CordovaBridge correctly on navigation.

If the bridge is reset incorrectly, its loadedUrl remains null, which
causes a NullPointerException when a non-file:// page tries to connect
to the bridge via prompt().

Relevant upstream code:
https://github.com/apache/cordova-android/blob/master/framework/src/org/apache/cordova/CordovaWebViewClient.java#L144
Merge pull request #147 from pwnall/fix_bridge

Reset CordovaBridge correctly on navigation.
Align SSL error behavior with Cordova-Android.

Cordova-Android ignores all SSL errors for debug builds, and fails on
SSL errors in release builds.

Crosswalk-Cordova-Android shows an alert dialog that lets the user
ignore the SSL error or cancel the request. This behavior is surprising
to Web platform developers, as typical browser behavior matches that of
Cordova-Android for release builds.

This change implements the Cordova-Android behavior, using the recently
introduced XWalkResourceClient::onReceivedSslError() hook.
Request focus on XWalkView to listener volume button

The XWalkView has no focus after loading web page, it can't receive the
onKeyListener and onKeyDown event, so the volume-button plugin and the
Cordova volume event can't work.

BUG=XWALK-2424 XWALK-2835
Merge pull request #148 from huningxin/crosswalk-10-fix-bridge

Reset CordovaBridge correctly on navigation.
Merge pull request #149 from pwnall/fix_ssl

Align SSL error behavior with Cordova-Android.
Merge pull request #150 from fujunwei/volume-button

Request focus on XWalkView to listener volume button