Cache the application context instead of Activity.

When storing a reference to a Context, ensure that it's the
Application context rather than Activity Context.

Bug: 5084293

Change-Id: Ib0be5f8ceb91846bb985d0813a8f22cabd44eaf8
diff --git a/src/com/android/browser/PreloadController.java b/src/com/android/browser/PreloadController.java
index 08e223f..dec22ff 100644
--- a/src/com/android/browser/PreloadController.java
+++ b/src/com/android/browser/PreloadController.java
@@ -41,7 +41,7 @@
     private Context mContext;
 
     public PreloadController(Context ctx) {
-        mContext = ctx;
+        mContext = ctx.getApplicationContext();
 
     }