Upstream various ios/web utilities and helpers

Upstreams miscellaneous helper classes and utility files that don't
have other dependencies, and can thus be built and tested as-is.

BUG=464810

Review URL: https://codereview.chromium.org/988383002

Cr-Commit-Position: refs/heads/master@{#319706}

1 files changed, 37 insertions, 0 deletions

diff --git a/ios/web/history_state_util.mm b/ios/web/history_state_util.mm
new file mode 100644
index 0000000..bdb11bce
--- /dev/null
+++ b/ios/web/history_state_util.mm
@@ -0,0 +1,37 @@
+// Copyright 2012 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.
+
+#import "ios/web/history_state_util.h"
+
+#include "base/logging.h"
+#include "url/gurl.h"
+
+namespace web {
+namespace history_state_util {
+
+bool IsHistoryStateChangeValid(const GURL& currentUrl,
+                               const GURL& toUrl) {
+  // These two checks are very important to the security of the page. We cannot
+  // allow the page to change the state to an invalid URL.
+  CHECK(currentUrl.is_valid());
+  CHECK(toUrl.is_valid());
+
+  return toUrl.GetOrigin() == currentUrl.GetOrigin();
+}
+
+GURL GetHistoryStateChangeUrl(const GURL& currentUrl,
+                              const GURL& baseUrl,
+                              const std::string& destination) {
+  if (!baseUrl.is_valid())
+    return GURL();
+  GURL toUrl = baseUrl.Resolve(destination);
+
+  if (!toUrl.is_valid() || !IsHistoryStateChangeValid(currentUrl, toUrl))
+    return GURL();
+
+  return toUrl;
+}
+
+}  // namespace history_state_util
+}  // namespace web