Change WebView.setNetworkAvailable plumbing.

Use new AwContents API for backwards compatibility rather than
informing the network stack.

Bug: 10154677
Change-Id: I85db125c7bbcd7ac8d4fce9e689df519a5ebe365
(cherry picked from commit 0363422b19ca6263dbfbcd0d9daa6d1abe5c6892)
diff --git a/chromium/java/com/android/webview/chromium/WebViewChromium.java b/chromium/java/com/android/webview/chromium/WebViewChromium.java
index ec5c1cc..0e778ca 100644
--- a/chromium/java/com/android/webview/chromium/WebViewChromium.java
+++ b/chromium/java/com/android/webview/chromium/WebViewChromium.java
@@ -237,7 +237,9 @@
     @Override
     public void setNetworkAvailable(boolean networkUp) {
         checkThread();
-        NetworkChangeNotifier.forceConnectivityState(networkUp);
+        // Note that this purely toggles the JS navigator.online property.
+        // It does not in affect chromium or network stack state in any way.
+        mAwContents.setNetworkAvailable(networkUp);
     }
 
     @Override