[Offline Pages] Minor improvement on consistency check.

Use set::find instead of std::find_if when looking for match of file
paths in order to make the process faster

Bug: 786240
Change-Id: I84dfdb7eb910bc120671520c6aca9b52a4971c7a
Reviewed-on: https://chromium-review.googlesource.com/802520
Commit-Queue: Yafei Duan <romax@chromium.org>
Reviewed-by: Peter Williamson <petewil@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521534}

components/offline_pages/core/model/persistent_pages_consistency_check_task.cc

@@ -111,6 +111,7 @@ bool CheckConsistencySync(const base::FilePath& archives_dir,
 
   auto persistent_page_infos = GetAllPersistentPageInfos(namespaces, db);
 
+  std::set<base::FilePath> persistent_page_info_paths;
   std::vector<int64_t> offline_ids_to_delete;
   for (const auto& page_info : persistent_page_infos) {
     // Get pages whose archive files does not exist and delete.
@@ -118,6 +119,9 @@ bool CheckConsistencySync(const base::FilePath& archives_dir,
       offline_ids_to_delete.push_back(page_info.offline_id);
       continue;
     }
+    // Extract existing file paths from |temp_page_infos| so that we can do a
+    // faster matching later.
+    persistent_page_info_paths.insert(page_info.file_path);
   }
   // Try to delete the pages by offline ids collected above.
   // If there's any database related errors, the function will return false,
@@ -131,14 +135,11 @@ bool CheckConsistencySync(const base::FilePath& archives_dir,
 
   // Delete any files in the persistent archive directory that no longer have
   // associated entries in the database.
-  // TODO(romax): https://crbug.com/786240.
   std::set<base::FilePath> archive_paths = GetAllArchives(archives_dir);
   std::vector<base::FilePath> files_to_delete;
   for (const auto& archive_path : archive_paths) {
-    if (std::find_if(persistent_page_infos.begin(), persistent_page_infos.end(),
-                     [&archive_path](const PageInfo& page_info) -> bool {
-                       return page_info.file_path == archive_path;
-                     }) == persistent_page_infos.end()) {
+    if (persistent_page_info_paths.find(archive_path) ==
+        persistent_page_info_paths.end()) {
       files_to_delete.push_back(archive_path);
     }
   }

components/offline_pages/core/model/temporary_pages_consistency_check_task.cc

@@ -108,6 +108,7 @@ bool CheckConsistencySync(const base::FilePath& archives_dir,
 
   auto temp_page_infos = GetAllTemporaryPageInfos(namespaces, db);
 
+  std::set<base::FilePath> temp_page_info_paths;
   std::vector<int64_t> offline_ids_to_delete;
   for (const auto& page_info : temp_page_infos) {
     // Get pages whose archive files does not exist and delete.
@@ -115,6 +116,9 @@ bool CheckConsistencySync(const base::FilePath& archives_dir,
       offline_ids_to_delete.push_back(page_info.offline_id);
       continue;
     }
+    // Extract existing file paths from |temp_page_infos| so that we can do a
+    // faster matching later.
+    temp_page_info_paths.insert(page_info.file_path);
   }
   // Try to delete the pages by offline ids collected above.
   // If there's any database related errors, the function will return false,
@@ -128,16 +132,11 @@ bool CheckConsistencySync(const base::FilePath& archives_dir,
 
   // Delete any files in the temporary archive directory that no longer have
   // associated entries in the database.
-  // TODO(romax): https://crbug.com/786240.
   std::set<base::FilePath> archive_paths = GetAllArchives(archives_dir);
   std::vector<base::FilePath> files_to_delete;
   for (const auto& archive_path : archive_paths) {
-    if (std::find_if(temp_page_infos.begin(), temp_page_infos.end(),
-                     [&archive_path](const PageInfo& page_info) -> bool {
-                       return page_info.file_path == archive_path;
-                     }) == temp_page_infos.end()) {
+    if (temp_page_info_paths.find(archive_path) == temp_page_info_paths.end())
       files_to_delete.push_back(archive_path);
-    }
   }
 
   return DeleteFiles(files_to_delete);