Halve the size of the PageView cache.

web/viewer.js

@@ -28,7 +28,7 @@ var DEFAULT_URL = 'compressed.tracemonkey-pldi-09.pdf';
 var DEFAULT_SCALE = 'auto';
 var DEFAULT_SCALE_DELTA = 1.1;
 var UNKNOWN_SCALE = 0;
-var CACHE_SIZE = 20;
+var CACHE_SIZE = 10;
 var CSS_UNITS = 96.0 / 72.0;
 var SCROLLBAR_PADDING = 40;
 var VERTICAL_PADDING = 5;