[Offline pages] Refactor URL conversions from TabAndroid

chrome/browser/android/tab_android.h

Index: chrome/browser/android/tab_android.h
diff --git a/chrome/browser/android/tab_android.h b/chrome/browser/android/tab_android.h
index aa79ad4b3252f78ac85c6cfea720b58d89962712..f15afa4140059fee8be7272958a75552b9dc4ffd 100644
--- a/chrome/browser/android/tab_android.h
+++ b/chrome/browser/android/tab_android.h
@@ -50,10 +50,6 @@ namespace infobars {
 class InfoBar;
 }
 
-namespace offline_pages {
-struct OfflinePageItem;
-}
-
 namespace prerender {
 class PrerenderManager;
 }
@@ -264,8 +260,6 @@ class TabAndroid : public CoreTabHelperDelegate,
 
   int64_t GetBookmarkIdHelper(bool only_editable) const;
 
-  const offline_pages::OfflinePageItem* GetOfflinePage(const GURL& url) const;
-
   JavaObjectWeakGlobalRef weak_java_tab_;
 
   // The identifier used by session restore for this tab.