Bug 539481 - tile.cache.size default should be set every time Fennec loads [r=dougt r=stechz]

mobile/chrome/content/BrowserView.js

@@ -47,7 +47,7 @@ const kBrowserFormZoomLevelMax = 2.0;
 const kBrowserViewZoomLevelPrecision = 10000;
 const kBrowserViewPrefetchBeginIdleWait = 1;    // seconds
 const kBrowserViewPrefetchBeginIdleWaitLoading = 10;    // seconds
-const kBrowserViewCacheSize = 15;
+const kBrowserViewCacheSize = 6;
 
 /**
  * A BrowserView maintains state of the viewport (browser, zoom level,
@@ -244,11 +244,27 @@ BrowserView.prototype = {
     let cacheSize = kBrowserViewCacheSize;
     try {
       cacheSize = gPrefService.getIntPref("tile.cache.size");
-      // XXX cacheSize still can be -1 even though new profile sets it to a positive value
-      if (cacheSize == -1)
-        cacheSize = kBrowserViewCacheSize;
     } catch(e) {}
 
+    if (cacheSize == -1) {
+      let sysInfo = Cc["@mozilla.org/system-info;1"].getService(Ci.nsIPropertyBag2);
+      let device = sysInfo.get("device");
+      switch (device) {
+#ifdef MOZ_PLATFORM_HILDON
+        case "Nokia N900":
+          cacheSize = 26;
+          break;
+        case "Nokia N8xx":
+          // N8xx has half the memory of N900 and crashes with higher numbers
+          cacheSize = 10;
+          break;
+#endif
+        default:
+          // Use a minimum number of tiles sice we don't know the device
+          cacheSize = 6;
+      }
+    }
+
     this._tileManager = new TileManager(this._appendTile, this._removeTile, this, cacheSize);
     this._visibleRectFactory = visibleRectFactory;
 
@@ -894,4 +910,3 @@ BrowserView.IdleServiceObserver.prototype = {
     bv._tileManager.setPrefetch(this._idle && !this._paused);
   }
 };
-

mobile/chrome/content/browser.js

@@ -647,29 +647,6 @@ var Browser = {
       this.setPluginState(false);
     }
 #endif
-    // set up the cache size
-    let cacheSize = -1;
-    try {
-      cacheSize = gPrefService.getIntPref("tile.cache.size");
-    } catch(e) {}
-
-    if (cacheSize == -1) {
-      switch (device) {
-#ifdef MOZ_PLATFORM_HILDON
-        case "Nokia N900":
-          cacheSize = 26;
-          break;
-        case "Nokia N8xx":
-          // N8xx has half the memory of N900 and crashes with higher numbers
-          cacheSize = 10;
-          break;
-#endif
-        default:
-          // Use a minimum number of tiles sice we don't know the device
-          cacheSize = 6;
-      }
-      gPrefService.setIntPref("tile.cache.size", cacheSize);
-    }
   },
 
   get browsers() {