Add a UI for setting JS flags.

The UI only shows up when 'about:debug' is typed in the address bar.
JS flags are a string '--heap-stats --log-gc' in V8 etc.

Currently this is only used by V8 build for debugging purpose.
diff --git a/src/com/android/browser/BrowserSettings.java b/src/com/android/browser/BrowserSettings.java
index 4f4d440..762149b 100644
--- a/src/com/android/browser/BrowserSettings.java
+++ b/src/com/android/browser/BrowserSettings.java
@@ -83,6 +83,7 @@
     private boolean appCacheEnabled = true;
     private String appCachePath;  // default value set in loadFromDb().
     private boolean domStorageEnabled = true;
+    private String jsFlags = "";
 
     private final static String TAG = "BrowserSettings";
 
@@ -94,6 +95,7 @@
     private boolean tracing = false;
     private boolean lightTouch = false;
     private boolean navDump = false;
+
     // Browser only settings
     private boolean doFlick = false;
 
@@ -327,7 +329,9 @@
             mTabControl.getBrowserActivity().setBaseSearchUrl(
                     p.getString("search_url", ""));
         }
-        update();
+        // JS flags is loaded from DB even if showDebugSettings is false,
+        // so that it can be set once and be effective all the time.
+        jsFlags = p.getString("js_engine_flags", "");
     }
 
     public String getPluginsPath() {
@@ -338,6 +342,10 @@
         return homeUrl;
     }
 
+    public String getJsFlags() {
+        return jsFlags;
+    }
+
     public void setHomePage(Context context, String url) {
         Editor ed = PreferenceManager.
                 getDefaultSharedPreferences(context).edit();