Bug 1219016 - Store application context in GeckoAppShell; r=snorp

This patch adds separate setter and getter for the application context
in GeckoAppShell. The existing getContext method is misused for both
application and activity context, so new methods are added to improve
consistency.

mobile/android/base/GeckoApp.java

@@ -1280,6 +1280,7 @@ public abstract class GeckoApp
         // When that's fixed, `this` can change to
         // `(GeckoApplication) getApplication()` here.
         GeckoAppShell.setContextGetter(this);
+        GeckoAppShell.setApplicationContext(getApplicationContext());
         GeckoAppShell.setGeckoInterface(this);
 
         Tabs.getInstance().attachToContext(this);

mobile/android/base/GeckoAppShell.java

@@ -2045,6 +2045,7 @@ public class GeckoAppShell
         }
     }
 
+    private static Context sApplicationContext;
     private static ContextGetter sContextGetter;
 
     @WrapForJNI(allowMultithread = true)
@@ -2056,6 +2057,14 @@ public class GeckoAppShell
         sContextGetter = cg;
     }
 
+    public static Context getApplicationContext() {
+        return sApplicationContext;
+    }
+
+    public static void setApplicationContext(final Context context) {
+        sApplicationContext = context;
+    }
+
     public static SharedPreferences getSharedPreferences() {
         if (sContextGetter == null) {
             throw new IllegalStateException("No ContextGetter; cannot fetch prefs.");

mobile/android/base/GeckoView.java

@@ -139,6 +139,10 @@ public class GeckoView extends LayerView
 
     private void init(Context context, String url, boolean doInit) {
 
+        if (GeckoAppShell.getApplicationContext() == null) {
+            GeckoAppShell.setApplicationContext(context.getApplicationContext());
+        }
+
         // Set the GeckoInterface if the context is an activity and the GeckoInterface
         // has not already been set
         if (context instanceof Activity && getGeckoInterface() == null) {