Add getView() API into CordovaWebView.

This API is to get the actual View.

The concrete webview implementation can use compositing instead of extending
underlying webview.

framework/src/org/apache/cordova/AndroidWebView.java

@@ -1078,4 +1078,8 @@ public class AndroidWebView extends WebView implements CordovaWebView {
         super.setLayoutParams(layoutParams);
     }
 
+    @Override
+    public View getView() {
+        return this;
+    }
 }

framework/src/org/apache/cordova/CordovaActivity.java

@@ -315,7 +315,7 @@ public class CordovaActivity extends Activity implements CordovaInterface {
 
         // Add web view but make it invisible while loading URL
         this.appView.setVisibility(View.INVISIBLE);
-        this.root.addView((View) this.appView);
+        this.root.addView((View) this.appView.getView());
         setContentView(this.root);
 
         // Clear cancel flag

framework/src/org/apache/cordova/CordovaWebView.java

@@ -17,6 +17,8 @@ public interface CordovaWebView {
     Object pluginManager = null;
     Object jsMessageQueue = null;
 
+    View getView();
+
     void setWebViewClient(CordovaWebViewClient webViewClient);
 
     void setWebChromeClient(CordovaChromeClient webChromeClient);