Fix up _some_web app directory StrictMode violations

base/android/java/src/org/chromium/base/FileUtils.java

Index: base/android/java/src/org/chromium/base/FileUtils.java
diff --git a/base/android/java/src/org/chromium/base/FileUtils.java b/base/android/java/src/org/chromium/base/FileUtils.java
new file mode 100644
index 0000000000000000000000000000000000000000..fbaec8c69e31044084a0a14920a38f0ca3b391a8
--- /dev/null
+++ b/base/android/java/src/org/chromium/base/FileUtils.java
@@ -0,0 +1,31 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.base;
+
+import java.io.File;
+
+/**
+ * Helper methods for dealing with Files.
+ */
+public class FileUtils {
+    private static final String TAG = "FileUtils";
+
+    /**
+     * Delete the given File and (if it's a directory) everything within it.
+     */
+    public static void recursivelyDeleteFile(File currentFile) {
+        assert !ThreadUtils.runningOnUiThread();
+        if (currentFile.isDirectory()) {
+            File[] files = currentFile.listFiles();
+            if (files != null) {
+                for (File file : files) {
+                    recursivelyDeleteFile(file);
+                }
+            }
+        }
+
+        if (!currentFile.delete()) Log.e(TAG, "Failed to delete: " + currentFile);
+    }
+}