android: Inflate viewport even more to render more tiles offscreen

Change-Id: I6a1f8bb8fd04e40ecd60eec87043e507ca6350e7

android/experimental/LOAndroid3/src/java/org/mozilla/gecko/gfx/ComposedTileLayer.java

@@ -165,7 +165,8 @@ public abstract class ComposedTileLayer extends Layer {
                     }
                 }
                 if (!contains) {
-                    LOEvent event = LOEventFactory.tileRequest(this, new TileIdentifier((int) x, (int) y, zoom, tileSize), false);
+                    TileIdentifier tileId = new TileIdentifier((int) x, (int) y, zoom, tileSize);
+                    LOEvent event = LOEventFactory.tileRequest(this, tileId, true);
                     event.mPriority = getTilePriority();
                     LOKitShell.sendEvent(event);
                 }
@@ -212,6 +213,9 @@ public abstract class ComposedTileLayer extends Layer {
         return RectF.intersects(currentViewport, tileId.getRect()) || currentViewport.contains(tileId.getRect());
     }
 
+    /**
+     * Invalidate tiles which intersect the input rect
+     */
     public void invalidateTiles(RectF rect) {
         RectF zoomedRect = RectUtils.inverseScale(rect, currentZoom);
 

android/experimental/LOAndroid3/src/java/org/mozilla/gecko/gfx/DynamicTileLayer.java

@@ -19,7 +19,7 @@ public class DynamicTileLayer extends ComposedTileLayer {
         return 0;
     }
 
-    protected IntSize getInflateFactor() {
-        return tileSize;
+    private IntSize getInflateFactor() {
+        return new IntSize(tileSize.width*2, tileSize.height*4);
     }
 }