Move File Existence Checker to a better location

Since it is used by both downloads and offline_pages, moving it to
a common namespace and directory

Bug: 814492
Change-Id: I8781730c3025087ff0ab0a5473f1ae4231dbf775
Reviewed-on: https://chromium-review.googlesource.com/939701
Commit-Queue: Peter Williamson <petewil@chromium.org>
Reviewed-by: Joy Ming <jming@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541677}

components/offline_items_collection/core/BUILD.gn

@@ -29,6 +29,7 @@ static_library("core") {
   ]
 
   deps = [
+    "utilities:utilities",
     "//ui/gfx/geometry",
   ]
 
@@ -56,6 +57,7 @@ source_set("unit_tests") {
 
   deps = [
     ":core",
+    "utilities:unit_tests",
     "//base/test:test_support",
     "//components/offline_items_collection/core/test_support",
   ]

components/offline_items_collection/core/utilities/BUILD.gn

+# Copyright 2018 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.
+
+source_set("utilities") {
+  sources = [
+    "file_existence_checker.h",
+  ]
+
+  public_deps = [
+    "//base",
+  ]
+}
+
+source_set("unit_tests") {
+  testonly = true
+
+  sources = [
+    "file_existence_checker_unittest.cc",
+  ]
+
+  deps = [
+    ":utilities",
+    "//base",
+    "//base/test:test_support",
+    "//testing/gtest",
+  ]
+}

components/offline_pages/core/file_existence_checker.h → components/offline_items_collection/core/utilities/file_existence_checker.h

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef COMPONENTS_OFFLINE_PAGES_CORE_FILE_EXISTENCE_CHECKER_H_
-#define COMPONENTS_OFFLINE_PAGES_CORE_FILE_EXISTENCE_CHECKER_H_
+#ifndef COMPONENTS_OFFLINE_ITEMS_COLLECTION_CORE_UTILITIES_FILE_EXISTENCE_CHECKER_H_
+#define COMPONENTS_OFFLINE_ITEMS_COLLECTION_CORE_UTILITIES_FILE_EXISTENCE_CHECKER_H_
 
 #include <utility>
 #include <vector>
@@ -18,7 +18,7 @@
 #include "base/sequenced_task_runner.h"
 #include "base/task_runner_util.h"
 
-namespace offline_pages {
+namespace offline_items_collection {
 
 // Class that checks in bulk, which of the provided set of file paths are not
 // pointing to an existing file.
@@ -62,6 +62,6 @@ class FileExistenceChecker {
   DISALLOW_COPY_AND_ASSIGN(FileExistenceChecker);
 };
 
-}  // namespace offline_pages
+}  // namespace offline_items_collection
 
-#endif  // COMPONENTS_OFFLINE_PAGES_CORE_FILE_EXISTENCE_CHECKER_H_
+#endif  // COMPONENTS_OFFLINE_ITEMS_COLLECTION_CORE_UTILITIES_FILE_EXISTENCE_CHECKER_H_

components/offline_pages/core/file_existence_checker_unittest.cc → components/offline_items_collection/core/utilities/file_existence_checker_unittest.cc

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "components/offline_pages/core/file_existence_checker.h"
+#include "components/offline_items_collection/core/utilities/file_existence_checker.h"
 
 #include <vector>
 
@@ -15,7 +15,7 @@
 #include "base/threading/thread_task_runner_handle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-namespace offline_pages {
+namespace offline_items_collection {
 
 using FileIdPairVector = FileExistenceChecker::FileWithIdCollection<int64_t>;
 using FileIdPairSet = std::set<std::pair<base::FilePath, int64_t>>;
@@ -94,4 +94,4 @@ TEST_F(FileExistenceCheckerTest, MissingFileFound) {
   EXPECT_EQ(0UL, missing_files.count(files[1]));
 }
 
-}  // namespace offline_pages
+}  // namespace offline_items_collection

components/offline_pages/core/BUILD.gn

@@ -18,7 +18,6 @@ static_library("core") {
     "client_namespace_constants.h",
     "client_policy_controller.cc",
     "client_policy_controller.h",
-    "file_existence_checker.h",
     "model/add_page_task.cc",
     "model/add_page_task.h",
     "model/add_page_to_download_manager_task.cc",
@@ -84,6 +83,7 @@ static_library("core") {
     "//base",
     "//components/filename_generation",
     "//components/keyed_service/core",
+    "//components/offline_items_collection/core/utilities",
     "//crypto",
     "//net",
     "//services/metrics/public/cpp:metrics_cpp",
@@ -147,7 +147,6 @@ source_set("unit_tests") {
     "archive_manager_unittest.cc",
     "archive_validator_unittest.cc",
     "client_policy_controller_unittest.cc",
-    "file_existence_checker_unittest.cc",
     "model/add_page_task_unittest.cc",
     "model/add_page_to_download_manager_task_unittest.cc",
     "model/clear_digest_task_unittest.cc",