drive: Fix a crash caused by an empty edit URL

For some reason, edit URL can be null in some entries, which
causes a crash.

Along the way, make |callback| parameter of DriveFilesystemInterface::Remove()
mandatory. The only caller in gdata_file_system_proxy.cc passes a non-null
callback.

BUG=144993
TEST=remove operation works as before


Review URL: https://chromiumcodereview.appspot.com/10880075

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@153603 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/chromeos/gdata/drive_file_system.cc

@@ -1212,6 +1212,8 @@ void DriveFileSystem::Remove(const FilePath& file_path,
     const FileOperationCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI) ||
          BrowserThread::CurrentlyOn(BrowserThread::IO));
+  DCHECK(!callback.is_null());
+
   RunTaskOnUIThread(base::Bind(&DriveFileSystem::RemoveOnUIThread,
                                ui_weak_ptr_,
                                file_path,
@@ -1222,6 +1224,7 @@ void DriveFileSystem::RemoveOnUIThread(
     const FilePath& file_path,
     const FileOperationCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
 
   // Get the edit URL of an entry at |file_path|.
   resource_metadata_->GetEntryInfoByPath(
@@ -1237,16 +1240,20 @@ void DriveFileSystem::RemoveOnUIThreadAfterGetEntryInfo(
     DriveFileError error,
     scoped_ptr<DriveEntryProto> entry_proto) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
 
   if (error != DRIVE_FILE_OK) {
-    if (!callback.is_null()) {
-      base::MessageLoopProxy::current()->PostTask(
-          FROM_HERE, base::Bind(callback, error));
-    }
+    callback.Run(error);
     return;
   }
-
   DCHECK(entry_proto.get());
+
+  // The edit URL can be empty for some reason.
+  if (entry_proto->edit_url().empty()) {
+    callback.Run(DRIVE_FILE_ERROR_NOT_FOUND);
+    return;
+  }
+
   drive_service_->DeleteDocument(
       GURL(entry_proto->edit_url()),
       base::Bind(&DriveFileSystem::RemoveResourceLocally,
@@ -2416,11 +2423,11 @@ void DriveFileSystem::RemoveResourceLocally(
     GDataErrorCode status,
     const GURL& /* document_url */) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
 
   DriveFileError error = util::GDataToDriveFileError(status);
   if (error != DRIVE_FILE_OK) {
-    if (!callback.is_null())
-      callback.Run(error);
+    callback.Run(error);
     return;
   }
 

chrome/browser/chromeos/gdata/drive_file_system.h

@@ -511,7 +511,7 @@ class DriveFileSystem : public DriveFileSystemInterface,
 
   // Callback for DriveServiceInterface::DeleteDocument. Removes the entry with
   // |resource_id| from the local snapshot of the filesystem and the cache.
-  // |document_url| is unused. |callback| may be null.
+  // |document_url| is unused. |callback| must not be null.
   void RemoveResourceLocally(const FileOperationCallback& callback,
                              const std::string& resource_id,
                              GDataErrorCode status,
@@ -797,6 +797,7 @@ class DriveFileSystem : public DriveFileSystemInterface,
 
   // Part of RemoveOnUIThread(). Called after GetEntryInfoByPath() is
   // complete.
+  // |callback| must not be null.
   void RemoveOnUIThreadAfterGetEntryInfo(
       const FileOperationCallback& callback,
       DriveFileError error,

chrome/browser/chromeos/gdata/drive_file_system_interface.h

@@ -227,6 +227,7 @@ class DriveFileSystemInterface {
   // TODO(satorux): is_recursive is not supported yet. crbug.com/138282
   //
   // Can be called from UI/IO thread. |callback| is run on the calling thread.
+  // |callback| must not be null.
   virtual void Remove(const FilePath& file_path,
                       bool is_recursive,
                       const FileOperationCallback& callback) = 0;