gdata: Make callback parameters mandatory for TransferFile functions

The public functions TransferFileFromRemoteToLocal() and
TransferFileFromLocalToRemote() are called from file_browser_private_api.cc
with callbacks, hence it's safe to make the callback parameter mandatory.

BUG=126634, 139446
TEST=out/Release/unit_tests --gtest_filter=GData*

Review URL: https://chromiumcodereview.appspot.com/10824240

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@150896 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/chromeos/gdata/gdata_file_system.cc

@@ -710,6 +710,7 @@ void GDataFileSystem::TransferFileFromRemoteToLocal(
     const FilePath& local_dest_file_path,
     const FileOperationCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
 
   GetFileByPath(remote_src_file_path,
       base::Bind(&GDataFileSystem::OnGetFileCompleteForTransferFile,
@@ -724,6 +725,7 @@ void GDataFileSystem::TransferFileFromLocalToRemote(
     const FilePath& remote_dest_file_path,
     const FileOperationCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
 
   // Make sure the destination directory exists.
   directory_service_->GetEntryInfoByPath(
@@ -743,22 +745,17 @@ void GDataFileSystem::TransferFileFromLocalToRemoteAfterGetEntryInfo(
     GDataFileError error,
     scoped_ptr<GDataEntryProto> entry_proto) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
 
   if (error != GDATA_FILE_OK) {
-    if (!callback.is_null()) {
-      base::MessageLoopProxy::current()->PostTask(
-          FROM_HERE, base::Bind(callback, error));
-    }
+    callback.Run(error);
     return;
   }
 
   DCHECK(entry_proto.get());
   if (!entry_proto->file_info().is_directory()) {
     // The parent of |remote_dest_file_path| is not a directory.
-    if (!callback.is_null()) {
-      base::MessageLoopProxy::current()->PostTask(
-          FROM_HERE, base::Bind(callback, GDATA_FILE_ERROR_NOT_A_DIRECTORY));
-    }
+    callback.Run(GDATA_FILE_ERROR_NOT_A_DIRECTORY);
     return;
   }
 
@@ -784,6 +781,7 @@ void GDataFileSystem::TransferFileForResourceId(
     std::string* resource_id) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(resource_id);
+  DCHECK(!callback.is_null());
 
   if (resource_id->empty()) {
     // If |resource_id| is empty, upload the local file as a regular file.
@@ -1038,11 +1036,10 @@ void GDataFileSystem::OnGetFileCompleteForTransferFile(
     const std::string& unused_mime_type,
     GDataFileType file_type) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
 
   if (error != GDATA_FILE_OK) {
-    if (!callback.is_null())
-      callback.Run(error);
-
+    callback.Run(error);
     return;
   }
 
@@ -1069,6 +1066,7 @@ void GDataFileSystem::CopyDocumentToDirectory(
     const FilePath::StringType& new_name,
     const FileOperationCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
 
   documents_service_->CopyDocument(resource_id, new_name,
       base::Bind(&GDataFileSystem::OnCopyDocumentCompleted,
@@ -2468,29 +2466,24 @@ void GDataFileSystem::OnCopyDocumentCompleted(
     GDataErrorCode status,
     scoped_ptr<base::Value> data) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
 
   GDataFileError error = util::GDataToGDataFileError(status);
   if (error != GDATA_FILE_OK) {
-    if (!callback.is_null())
-      callback.Run(error);
-
+    callback.Run(error);
     return;
   }
 
   scoped_ptr<DocumentEntry> doc_entry(DocumentEntry::ExtractAndParse(*data));
   if (!doc_entry.get()) {
-    if (!callback.is_null())
-      callback.Run(GDATA_FILE_ERROR_FAILED);
-
+    callback.Run(GDATA_FILE_ERROR_FAILED);
     return;
   }
 
   GDataEntry* entry = GDataEntry::FromDocumentEntry(
       NULL, doc_entry.get(), directory_service_.get());
   if (!entry) {
-    if (!callback.is_null())
-      callback.Run(GDATA_FILE_ERROR_FAILED);
-
+    callback.Run(GDATA_FILE_ERROR_FAILED);
     return;
   }
 

chrome/browser/chromeos/gdata/gdata_file_system.h

@@ -201,6 +201,7 @@ class GDataFileSystem : public GDataFileSystemInterface,
   // TransferRegularFile.
   //
   // Must be called from *UI* thread. |callback| is run on the calling thread.
+  // |callback| must not be null.
   void TransferFileForResourceId(const FilePath& local_file_path,
                                  const FilePath& remote_dest_file_path,
                                  const FileOperationCallback& callback,
@@ -321,6 +322,7 @@ class GDataFileSystem : public GDataFileSystemInterface,
   // |local_dest_file_path|.
   //
   // Can be called from UI thread. |callback| is run on the calling thread.
+  // |callback| must not be null.
   void OnGetFileCompleteForTransferFile(const FilePath& local_dest_file_path,
                                         const FileOperationCallback& callback,
                                         GDataFileError error,
@@ -346,6 +348,7 @@ class GDataFileSystem : public GDataFileSystemInterface,
   // and names the copied document as |new_name|.
   //
   // Can be called from UI thread. |callback| is run on the calling thread.
+  // |callback| must not be null.
   void CopyDocumentToDirectory(const FilePath& dir_path,
                                const std::string& resource_id,
                                const FilePath::StringType& new_name,
@@ -413,6 +416,7 @@ class GDataFileSystem : public GDataFileSystemInterface,
       const FilePath& cache_file_path);
 
   // Callback for handling document copy attempt.
+  // |callback| must not be null.
   void OnCopyDocumentCompleted(const FilePath& dir_path,
                                const FileOperationCallback& callback,
                                GDataErrorCode status,
@@ -742,7 +746,7 @@ class GDataFileSystem : public GDataFileSystemInterface,
                                  const base::Closure& callback);
 
   // Part of CopyOnUIThread(). Called after GetEntryInfoPairByPaths() is
-  // complete.
+  // complete. |callback| must not be null.
   void CopyOnUIThreadAfterGetEntryInfoPair(
     const FilePath& dest_file_path,
     const FileOperationCallback& callback,

chrome/browser/chromeos/gdata/gdata_file_system_interface.h

@@ -146,6 +146,7 @@ class GDataFileSystemInterface {
   // |local_dest_file_path| is the destination path on the local file system.
   //
   // Must be called from *UI* thread. |callback| is run on the calling thread.
+  // |callback| must not be null.
   virtual void TransferFileFromRemoteToLocal(
       const FilePath& remote_src_file_path,
       const FilePath& local_dest_file_path,
@@ -157,6 +158,7 @@ class GDataFileSystemInterface {
   // system.
   //
   // Must be called from *UI* thread. |callback| is run on the calling thread.
+  // |callback| must not be null.
   virtual void TransferFileFromLocalToRemote(
       const FilePath& local_src_file_path,
       const FilePath& remote_dest_file_path,