Delete empty bugreport files onError

Bug: 152839953
Test: Take another bugreport, while one is in progress.
Without this change: bugreport files for the second bugreport can be
seen in /bugreports
With this change: no file for the second bugreport can be seen. This
is the expected behavior.

Change-Id: I45c1f66f3a52ba9a31413cf9748bc5504eaa65d0

packages/Shell/src/com/android/shell/BugreportProgressService.java

@@ -363,6 +363,7 @@ public class BugreportProgressService extends Service {
         public void onError(@BugreportErrorCode int errorCode) {
             synchronized (mLock) {
                 stopProgressLocked(mInfo.id);
+                mInfo.deleteEmptyFiles();
             }
             Log.e(TAG, "Bugreport API callback onError() errorCode = " + errorCode);
             return;
@@ -1979,6 +1980,22 @@ public class BugreportProgressService extends Service {
             bugreportFile.delete();
         }
 
+        /**
+         * Deletes empty files for a given bugreport.
+         */
+        private void deleteEmptyFiles() {
+            if (bugreportFile.length() == 0) {
+                Log.i(TAG, "Deleting empty bugreport file: " + bugreportFile);
+                bugreportFile.delete();
+            }
+            for (File file : screenshotFiles) {
+                if (file.length() == 0) {
+                    Log.i(TAG, "Deleting empty screenshot file: " + file);
+                    file.delete();
+                }
+            }
+        }
+
         /**
          * Rename all screenshots files so that they contain the new {@code name} instead of the
          * {@code initialName} if user has changed it.