DOM Storage: Remove unused SQLite migration code.

Change-Id: I3673a9a4411c00b72a3e96b405ce726c9632ca4a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2359235
Commit-Queue: Victor Costan <pwnall@chromium.org>
Auto-Submit: Victor Costan <pwnall@chromium.org>
Reviewed-by: Marijn Kruisselbrink <mek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#798825}

components/services/storage/dom_storage/legacy_dom_storage_database.cc

@@ -18,9 +18,7 @@ LegacyDomStorageDatabase::LegacyDomStorageDatabase(
     const base::FilePath& file_path,
     std::unique_ptr<FilesystemProxy> filesystem_proxy)
     : file_path_(file_path), filesystem_proxy_(std::move(filesystem_proxy)) {
-  // Note: in normal use we should never get an empty backing path here.
-  // However, the unit test for this class can contruct an instance
-  // with an empty path.
+  DCHECK(!file_path_.empty());
   Init();
 }
 
@@ -167,14 +165,6 @@ bool LegacyDomStorageDatabase::LazyOpen(bool create_if_needed) {
   // (tiny amount of) problems that mmap() may cause.
   db_->set_mmap_disabled();
 
-  if (file_path_.empty()) {
-    // This code path should only be triggered by unit tests.
-    if (!db_->OpenInMemory()) {
-      NOTREACHED() << "Unable to open DOM storage database in memory.";
-      failed_to_open_ = true;
-      return false;
-    }
-  } else {
   if (!db_->Open(file_path_)) {
     LOG(ERROR) << "Unable to open DOM storage database at "
                << file_path_.value() << " error: " << db_->GetErrorMessage();
@@ -183,7 +173,6 @@ bool LegacyDomStorageDatabase::LazyOpen(bool create_if_needed) {
     failed_to_open_ = true;
     return false;
   }
-  }
 
   // sql::Database uses UTF-8 encoding, but WebCore style databases use
   // UTF-16, so ensure we match.