[Offline pages] Filter out pages cached by different tabs on tab helper

chrome/browser/android/offline_pages/offline_page_utils.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/android/offline_pages/offline_page_utils.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/android/offline_pages/offline_page_mhtml_archiver.h"
 #include "chrome/browser/android/offline_pages/offline_page_model_factory.h"
 #include "chrome/browser/android/offline_pages/offline_page_tab_helper.h"
+#include "chrome/browser/android/tab_android.h"
 #include "components/offline_pages/offline_page_feature.h"
 #include "components/offline_pages/offline_page_item.h"
 #include "components/offline_pages/offline_page_model.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/web_contents.h"
 #include "url/gurl.h"
 
 namespace offline_pages {
 namespace {
 
@@ skipping 143 matching lines @@
   offline_page_model->MarkPageAccessed(offline_page->offline_id);
 }
 
 const OfflinePageItem* OfflinePageUtils::GetOfflinePageFromWebContents(
     content::WebContents* web_contents) {
   OfflinePageTabHelper* tab_helper =
       OfflinePageTabHelper::FromWebContents(web_contents);
   return tab_helper ? tab_helper->offline_page() : nullptr;
 }
 
+// static
+bool OfflinePageUtils::GetTabId(content::WebContents* web_contents,
+                                int* tab_id) {
+  TabAndroid* tab_android = TabAndroid::FromWebContents(web_contents);
+  if (!tab_android)
+    return false;
+  *tab_id = tab_android->GetAndroidId();
+  return true;
+}
+
 }  // namespace offline_pages