android: Add a method to let Java know whether a prerender has finished loading.

chrome/browser/prerender/external_prerender_handler_android.h

Index: chrome/browser/prerender/external_prerender_handler_android.h
diff --git a/chrome/browser/prerender/external_prerender_handler_android.h b/chrome/browser/prerender/external_prerender_handler_android.h
index 01862274885a75678035284da3f46ca4cbc1f9d0..6aae904e67d11461c24ec3451da77ccd613e8d9c 100644
--- a/chrome/browser/prerender/external_prerender_handler_android.h
+++ b/chrome/browser/prerender/external_prerender_handler_android.h
@@ -48,6 +48,13 @@ class ExternalPrerenderHandlerAndroid {
                                 GURL url,
                                 content::WebContents* web_contents);
 
+  // Whether the PrerenderManager associated with the given profile has any
+  // prerenders for the url, and the prerender has finished loading.
+  static bool HasPrerenderedAndFinishedLoadingUrl(
+      Profile* profile,
+      GURL url,
+      content::WebContents* web_contents);
+
   static bool RegisterExternalPrerenderHandlerAndroid(JNIEnv* env);
 
  private: