Bug 522514: Make tile capacity a preference [r=stechz]

mobile/app/mobile.js

@@ -75,6 +75,13 @@ pref("browser.cache.disk.capacity", 0); // kilobytes
 pref("browser.cache.memory.enable", true);
 pref("browser.cache.memory.capacity", 1024); // kilobytes
 
+/* tile cache prefs */
+#ifdef WINCE
+pref("tile.cache.size", 15); // tiles
+#else
+pref("tile.cache.size", 30); // tiles
+#endif
+
 /* image cache prefs */
 pref("image.cache.size", 1048576); // bytes
 

mobile/chrome/content/BrowserView.js

@@ -44,7 +44,7 @@ const kBrowserViewZoomLevelMin = 0.2;
 const kBrowserViewZoomLevelMax = 4.0;
 const kBrowserViewZoomLevelPrecision = 10000;
 const kBrowserViewPrefetchBeginIdleWait = 1;    // seconds
-
+const kBrowserViewCacheSize = 15;
 
 /**
  * A BrowserView maintains state of the viewport (browser, zoom level,
@@ -232,7 +232,12 @@ BrowserView.prototype = {
     this._browserViewportState = null;
     this._contentWindow = null;
     this._renderMode = 0;
-    this._tileManager = new TileManager(this._appendTile, this._removeTile, this);
+    
+    let cacheSize = kBrowserViewCacheSize;
+    try {
+      cacheSize = gPrefService.getIntPref("tile.cache.size");
+    } catch(e) {}
+    this._tileManager = new TileManager(this._appendTile, this._removeTile, this, cacheSize);
     this._visibleRectFactory = visibleRectFactory;
 
     this._idleServiceObserver = new BrowserView.IdleServiceObserver(this);

mobile/chrome/content/TileManager.js.in

@@ -98,8 +98,6 @@ const kTileWidth  = Math.pow(2, kTileExponentWidth);   // 2^9 = 512
 const kTileHeight = Math.pow(2, kTileExponentHeight);  // 2^9 = 512
 const kTileCrawlTimeCap = 100;    // millis
 const kTileCrawlComeAgain = 0;    // millis
-const kInitialCacheCapacity = 15;
-
 
 /**
  * The Tile Manager!
@@ -113,7 +111,7 @@ const kInitialCacheCapacity = 15;
  * @param fakeWidth The width of the widest possible visible rectangle, e.g.
  * the width of the screen.  This is used in setting the zoomLevel.
  */
-function TileManager(appendTile, removeTile, browserView) {
+function TileManager(appendTile, removeTile, browserView, cacheSize) {
   /* backref to the BrowserView object that owns us */
   this._browserView = browserView;
 
@@ -124,7 +122,7 @@ function TileManager(appendTile, removeTile, browserView) {
   /* tile cache holds tile objects and pools them under a given capacity */
   let self = this;
   this._tileCache = new TileManager.TileCache(function(tile) { self._removeTileSafe(tile); },
-                                              -1, -1, kInitialCacheCapacity);
+                                              -1, -1, cacheSize);
 
   /* Rectangle within the viewport that is visible to the user.  It is "critical"
    * in the sense that it must be rendered as soon as it becomes dirty, and tiles