Only commit cookie changes in prerenders after a prerender is shown

chrome/android/java/src/org/chromium/chrome/browser/prerender/ExternalPrerenderHandler.java

Index: chrome/android/java/src/org/chromium/chrome/browser/prerender/ExternalPrerenderHandler.java
===================================================================
--- chrome/android/java/src/org/chromium/chrome/browser/prerender/ExternalPrerenderHandler.java	(revision 269838)
+++ chrome/android/java/src/org/chromium/chrome/browser/prerender/ExternalPrerenderHandler.java	(working copy)
@@ -38,12 +38,18 @@
         return nativeHasPrerenderedUrl(profile, url, webContentsPtr);
     }
 
+    public static boolean hasCookieStoreLoaded(Profile profile)  {
+        return nativeHasCookieStoreLoaded(profile);
+    }
+
     private static native long nativeInit();
     private static native boolean nativeAddPrerender(
             long nativeExternalPrerenderHandlerAndroid, Profile profile,
             long webContentsPtr, String url, String referrer, int width, int height);
     private static native boolean nativeHasPrerenderedUrl(
             Profile profile, String url, long webContentsPtr);
+    private static native boolean nativeHasCookieStoreLoaded(
+            Profile profile);
     private static native void nativeCancelCurrentPrerender(
             long nativeExternalPrerenderHandlerAndroid);
 }