Add the plumbing to enable DRP

android_webview/java/src/org/chromium/android_webview/AwContentsStatics.java

Index: android_webview/java/src/org/chromium/android_webview/AwContentsStatics.java
diff --git a/android_webview/java/src/org/chromium/android_webview/AwContentsStatics.java b/android_webview/java/src/org/chromium/android_webview/AwContentsStatics.java
index a7fd4f8470f5ee9f36b726215852159d136cd05c..b7c8ced1bf74146cc28d72f625455da8fb37ccbb 100644
--- a/android_webview/java/src/org/chromium/android_webview/AwContentsStatics.java
+++ b/android_webview/java/src/org/chromium/android_webview/AwContentsStatics.java
@@ -49,12 +49,22 @@ public class AwContentsStatics {
      * Set Data Reduction Proxy key for authentication.
      */
     public static void setDataReductionProxyKey(String key) {
+        ThreadUtils.assertOnUiThread();
         nativeSetDataReductionProxyKey(key);
     }
 
+    /*
+     * Enable or disable data reduction proxy.
+     */
+    public static void setDataReductionProxyEnabled(boolean enabled) {
+        ThreadUtils.assertOnUiThread();
+        nativeSetDataReductionProxyEnabled(enabled);
+    }
+
     //--------------------------------------------------------------------------------------------
     //  Native methods
     //--------------------------------------------------------------------------------------------
     private static native void nativeClearClientCertPreferences(Runnable callback);
     private static native void nativeSetDataReductionProxyKey(String key);
+    private static native void nativeSetDataReductionProxyEnabled(boolean enabled);
 }