Windows fix for exportSyncfsFolderToLocalFs API.

DeleteFile may return false is the file to be deleted does not exist
on windows. Don't abort export syncfs folder operation if delete
file fails.

BUG=

Review URL: https://chromiumcodereview.appspot.com/19828006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@213322 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/extensions/api/developer_private/developer_private_api.cc

@@ -920,15 +920,9 @@ bool DeveloperPrivateExportSyncfsFolderToLocalfsFunction::RunImpl() {
 
 void DeveloperPrivateExportSyncfsFolderToLocalfsFunction::
     ClearPrexistingDirectoryContent(const base::FilePath& project_path) {
-  if (!base::DeleteFile(project_path, true/*recursive*/)) {
-    SetError("Error in copying files from sync filesystem.");
-    content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
-        base::Bind(&DeveloperPrivateExportSyncfsFolderToLocalfsFunction::
-                       SendResponse,
-                   this,
-                   false));
-    return;
-  }
+
+  // Clear the project directory before copying new files.
+  base::DeleteFile(project_path, true/*recursive*/);
 
   pendingCopyOperationsCount_ = 1;