Add debug option to disable performance features for testing

Change-Id: I508448907a83fb32028cb28eb64b72f97a863fd0
diff --git a/src/com/android/browser/BaseUi.java b/src/com/android/browser/BaseUi.java
index 2d53daa..026e661 100644
--- a/src/com/android/browser/BaseUi.java
+++ b/src/com/android/browser/BaseUi.java
@@ -686,8 +686,9 @@
     }
 
     public static boolean isUiLowPowerMode() {
-        return BrowserCommandLine.hasSwitch("ui-low-power-mode") ||
-            BrowserSettings.getInstance().isPowerSaveModeEnabled();
+        return BrowserCommandLine.hasSwitch("ui-low-power-mode")
+            || BrowserSettings.getInstance().isPowerSaveModeEnabled()
+            || BrowserSettings.getInstance().isDisablePerfFeatures();
     }
 
     // -------------------------------------------------------------------------