Set root resource ID upon full feed update.

chrome/browser/chromeos/drive/drive_resource_metadata.cc

Index: chrome/browser/chromeos/drive/drive_resource_metadata.cc
diff --git a/chrome/browser/chromeos/drive/drive_resource_metadata.cc b/chrome/browser/chromeos/drive/drive_resource_metadata.cc
index ba8385397598d5c19f9e205751bcdda174d626f1..9e98b6f7b804e7c848a37e50239394fd170f4991 100644
--- a/chrome/browser/chromeos/drive/drive_resource_metadata.cc
+++ b/chrome/browser/chromeos/drive/drive_resource_metadata.cc
@@ -187,8 +187,8 @@ DriveResourceMetadata::DriveResourceMetadata()
       initialized_(false),
       ALLOW_THIS_IN_INITIALIZER_LIST(weak_ptr_factory_(this)) {
   root_ = CreateDriveDirectory().Pass();
-  if (!google_apis::util::IsDriveV2ApiEnabled())
-    InitializeRootEntry(kDriveRootDirectoryResourceId);
+  root_->set_title(kDriveRootDirectory);
+  root_->SetBaseNameFromTitle();
 }
 
 DriveResourceMetadata::~DriveResourceMetadata() {
@@ -208,11 +208,9 @@ scoped_ptr<DriveDirectory> DriveResourceMetadata::CreateDriveDirectory() {
   return scoped_ptr<DriveDirectory>(new DriveDirectory(this));
 }
 
-void DriveResourceMetadata::InitializeRootEntry(const std::string& root_id) {
-  root_ = CreateDriveDirectory().Pass();
-  root_->set_title(kDriveRootDirectory);
-  root_->SetBaseNameFromTitle();
-  root_->set_resource_id(root_id);
+void DriveResourceMetadata::InitializeRootEntry(const std::string& id) {
+  DCHECK(root_->resource_id().empty());
+  root_->set_resource_id(id);
   AddEntryToResourceMap(root_.get());
 }
 
@@ -220,11 +218,17 @@ void DriveResourceMetadata::ClearRoot() {
   if (!root_.get())
     return;
 
+  // The root is not yet initialized.
+  if (root_->resource_id().empty())
+    return;
+
   // Note that children have a reference to root_,
   // so we need to delete them here.
   root_->RemoveChildren();
   RemoveEntryFromResourceMap(root_->resource_id());
   DCHECK(resource_map_.empty());
+  // The resource_map_ should be empty here, but to make sure for non-Debug
+  // build.
   resource_map_.clear();
   root_.reset();
 }
@@ -342,7 +346,7 @@ void DriveResourceMetadata::RemoveEntryFromParent(
   DCHECK(!callback.is_null());
 
   // Disallow deletion of root.
-  if (resource_id == kDriveRootDirectoryResourceId) {
+  if (resource_id == root_->resource_id()) {
     PostFileMoveCallbackError(callback, DRIVE_FILE_ERROR_ACCESS_DENIED);
     return;
   }
@@ -630,7 +634,6 @@ void DriveResourceMetadata::InitResourceMap(
   DCHECK(!resource_metadata_db_.get());
   DCHECK(!callback.is_null());
 
-
   SerializedMap* serialized_resources = &create_params->serialized_resources;
   resource_metadata_db_ = create_params->db.Pass();
   if (serialized_resources->empty()) {
@@ -638,6 +641,8 @@ void DriveResourceMetadata::InitResourceMap(
     return;
   }
 
+  // Save root directory resource ID as ClearRoot() resets |root_|.
+  std::string saved_root_resource_id = root_->resource_id();
   ClearRoot();
 
   // Version check.
@@ -699,7 +704,7 @@ void DriveResourceMetadata::InitResourceMap(
       } else {
         NOTREACHED() << "Parent is not a directory " << parent->resource_id();
       }
-    } else if (entry->resource_id() == kDriveRootDirectoryResourceId) {
+    } else if (entry->resource_id() == saved_root_resource_id) {
       root_.reset(entry->AsDriveDirectory());
       DCHECK(root_.get());
       AddEntryToResourceMap(root_.get());
@@ -785,6 +790,9 @@ bool DriveResourceMetadata::ParseFromString(
   }
 
   root_->FromProto(proto.drive_directory());
+  // Call AddEntryToResourceMap() instead of InitializeRootEntry() as the root
+  // resource is already set from proto.
+  AddEntryToResourceMap(root_.get());
 
   initialized_ = true;
   largest_changestamp_ = proto.largest_changestamp();