[Sync] Make OnDiskDirectoryBackingStore base class for deferred DBS

DODDBS now derives from ODDBS so it can access the backing file path.

Remove backing file path from DODDBS and use ODDBS's accessor method
instead.

Rename db_is_on_disk_ to created_on_disk_.

Rename backing_filepath_ to backing_file_path_ to match base::FilePath.

Move duplicated empty change detection logic out of DBS and into
SaveChangesSnapshot.

Format CL with "git cl format".

BUG=475557

Review URL: https://codereview.chromium.org/1097693004

Cr-Commit-Position: refs/heads/master@{#325908}

1 files changed, 19 insertions, 12 deletions

diff --git a/sync/syncable/on_disk_directory_backing_store.cc b/sync/syncable/on_disk_directory_backing_store.cc
index e6f284d..918dc07 100644
--- a/sync/syncable/on_disk_directory_backing_store.cc
+++ b/sync/syncable/on_disk_directory_backing_store.cc
@@ -24,13 +24,15 @@ enum HistogramResultEnum {
 }  // namespace
 
 OnDiskDirectoryBackingStore::OnDiskDirectoryBackingStore(
-    const std::string& dir_name, const base::FilePath& backing_filepath)
+    const std::string& dir_name,
+    const base::FilePath& backing_file_path)
     : DirectoryBackingStore(dir_name),
       allow_failure_for_test_(false),
-      backing_filepath_(backing_filepath) {
+      backing_file_path_(backing_file_path) {
 }
 
-OnDiskDirectoryBackingStore::~OnDiskDirectoryBackingStore() { }
+OnDiskDirectoryBackingStore::~OnDiskDirectoryBackingStore() {
+}
 
 DirOpenResult OnDiskDirectoryBackingStore::TryLoad(
     Directory::MetahandlesMap* handles_map,
@@ -40,7 +42,7 @@ DirOpenResult OnDiskDirectoryBackingStore::TryLoad(
   DCHECK(CalledOnValidThread());
 
   if (!IsOpen()) {
-    if (!Open(backing_filepath_))
+    if (!Open(backing_file_path_))
       return FAILED_OPEN_DATABASE;
   }
 
@@ -57,7 +59,6 @@ DirOpenResult OnDiskDirectoryBackingStore::TryLoad(
     return FAILED_DATABASE_CORRUPT;
 
   return OPENED;
-
 }
 
 DirOpenResult OnDiskDirectoryBackingStore::Load(
@@ -65,11 +66,12 @@ DirOpenResult OnDiskDirectoryBackingStore::Load(
     JournalIndex* delete_journals,
     MetahandleSet* metahandles_to_purge,
     Directory::KernelLoadInfo* kernel_load_info) {
+  DCHECK(CalledOnValidThread());
   DirOpenResult result = TryLoad(handles_map, delete_journals,
                                  metahandles_to_purge, kernel_load_info);
   if (result == OPENED) {
-    UMA_HISTOGRAM_ENUMERATION(
-        "Sync.DirectoryOpenResult", FIRST_TRY_SUCCESS, RESULT_COUNT);
+    UMA_HISTOGRAM_ENUMERATION("Sync.DirectoryOpenResult", FIRST_TRY_SUCCESS,
+                              RESULT_COUNT);
     return OPENED;
   }
 
@@ -82,16 +84,16 @@ DirOpenResult OnDiskDirectoryBackingStore::Load(
 
   ResetAndCreateConnection();
 
-  base::DeleteFile(backing_filepath_, false);
+  base::DeleteFile(backing_file_path_, false);
 
   result = TryLoad(handles_map, delete_journals, metahandles_to_purge,
                    kernel_load_info);
   if (result == OPENED) {
-    UMA_HISTOGRAM_ENUMERATION(
-        "Sync.DirectoryOpenResult", SECOND_TRY_SUCCESS, RESULT_COUNT);
+    UMA_HISTOGRAM_ENUMERATION("Sync.DirectoryOpenResult", SECOND_TRY_SUCCESS,
+                              RESULT_COUNT);
   } else {
-    UMA_HISTOGRAM_ENUMERATION(
-        "Sync.DirectoryOpenResult", SECOND_TRY_FAILURE, RESULT_COUNT);
+    UMA_HISTOGRAM_ENUMERATION("Sync.DirectoryOpenResult", SECOND_TRY_FAILURE,
+                              RESULT_COUNT);
   }
 
   return result;
@@ -109,5 +111,10 @@ void OnDiskDirectoryBackingStore::ReportFirstTryOpenFailure() {
   NOTREACHED() << "Crashing to preserve corrupt sync database";
 }
 
+const base::FilePath& OnDiskDirectoryBackingStore::backing_file_path() const {
+  DCHECK(CalledOnValidThread());
+  return backing_file_path_;
+}
+
 }  // namespace syncable
 }  // namespace syncer