Revert "Disable child warm-up patch"

This reverts commit 386c12339da2fe1e321d13ca2975dd19094e4115.

Change-Id: I650ddc9a659d52221a18901253c82f68722be431
diff --git a/src/com/android/browser/NavigationBarBase.java b/src/com/android/browser/NavigationBarBase.java
index 5591558..53bd973 100644
--- a/src/com/android/browser/NavigationBarBase.java
+++ b/src/com/android/browser/NavigationBarBase.java
@@ -429,6 +429,7 @@
             setFocusState(hasFocus);
         }
         if (hasFocus) {
+            Engine.warmUpChildProcessAsync(mUiController.getActivity().getApplicationContext());
             mBaseUi.showTitleBar();
             if (!BrowserSettings.getInstance().isPowerSaveModeEnabled()) {
                 //Notify about anticipated network activity