[android_webview] Split out an apk folder from the glue folder.

android_webview/apk/java/proguard.flags

 # Most of the flags in this file are duplicated to refer to both the pre- and
 # post-jarjar remapping versions of the class names. This enables the same
 # config file to be used whether jarjar is enabled or not.
 
 
 # Keep the factory and its public members; it's the main entry point used by the
 # framework.
 -keep class com.android.webview.chromium.WebViewChromiumFactoryProvider {
     public *;
 }
@@ skipping 81 matching lines @@
   <init>(...);
 }
 
 -keep class com.android.org.chromium.ui.ColorPickerSimple {
   <init>(...);
 }
 
 -keep class com.android.org.chromium.ui.ColorPickerMoreButton {
   <init>(...);
 }