CB-8467

Added support for hiding the web view container.  This maintains the browser
session without closing it.  The browser window can be repeatedly hidden and
shown.

** This has only been tested on android and ios **

amazon/android:
An additional `hide` action was added to `InAppBrowser#execute`.  It is
identical to `show`, except that it calls `dialog.hide()` instead.

blackberry10:
no changes

firefoxos:
Added a `hide` method that is identical to `show`, indicating it is not
supported.

ios:
Added a `hide` method that is identical to `show`, except that it uses
`dismissViewControllerAnimated`.  It checks the value of
`_previousStatusBarStyle`.  If it is `-1`, the method returns with no
action performed.  If it is not, it is set to `-1.`

ubuntu:
Added a `hide` method that sets `CordovaWrapper.global.inappbrowser.visible` to
`false`.

windows:
Added a `hide` method that sets `browserWrap.style.display` to `none`.

wp:
Added a `hide` method that is identical to `show`, except that it sets
`browser.Visibility` to `Visibility.Collapsed` and sets `AppBar.IsVisible` to
`false`.

src/android/InAppBrowser.java

@@ -253,6 +253,17 @@ public class InAppBrowser extends CordovaPlugin {
             pluginResult.setKeepCallback(true);
             this.callbackContext.sendPluginResult(pluginResult);
         }
+        else if (action.equals("hide")) {
+            this.cordova.getActivity().runOnUiThread(new Runnable() {
+                @Override
+                public void run() {
+                    dialog.hide();
+                }
+            });
+            PluginResult pluginResult = new PluginResult(PluginResult.Status.OK);
+            pluginResult.setKeepCallback(true);
+            this.callbackContext.sendPluginResult(pluginResult);
+        }
         else {
             return false;
         }