[Spelling] fix spelling of registered in a comment.

No logic changes. Just a spelling fix in a comment.

TBR=blundell@chromium.org

Bug: None
Change-Id: Ice5f572a695706850fb1a1e88d91a229ab7034df
Reviewed-on: https://chromium-review.googlesource.com/996895Reviewed-by: Dave Schuyler <dschuyler@chromium.org>
Commit-Queue: Dave Schuyler <dschuyler@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548300}

components/download/public/common/download_file_impl.h

@@ -103,7 +103,7 @@ class COMPONENTS_DOWNLOAD_EXPORT DownloadFileImpl : public DownloadFile {
     // Registers the callback that will be called when data is ready.
     void RegisterDataReadyCallback(
         const mojo::SimpleWatcher::ReadyCallback& callback);
-    // Clears the callback that is registed when data is ready.
+    // Clears the callback that is registered when data is ready.
     void ClearDataReadyCallback();
 
     // Gets the status of the input stream when the stream completes.