Implement DelegationTracker for tracking delegated permissions to RenderFrameHosts

chrome/browser/permissions/delegation_tracker.cc

Index: chrome/browser/permissions/delegation_tracker.cc
diff --git a/chrome/browser/permissions/delegation_tracker.cc b/chrome/browser/permissions/delegation_tracker.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d705a03115a9eadd63b9d2c492ee4316cab9a58c
--- /dev/null
+++ b/chrome/browser/permissions/delegation_tracker.cc
@@ -0,0 +1,104 @@
+// Copyright 2016 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.
+
+#include "chrome/browser/permissions/delegation_tracker.h"
+
+#include <unordered_set>
+
+#include "base/memory/ptr_util.h"
+#include "chrome/browser/permissions/permission_util.h"
+#include "content/public/browser/permission_type.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_observer.h"
+
+class DelegationTracker::DelegatedForChild : content::WebContentsObserver {
+ public:
+  DelegatedForChild(content::RenderFrameHost* child_rfh,
+                    const std::vector<content::PermissionType>& permissions,
+                    const base::Callback<void(content::RenderFrameHost*)>&
+                        rfh_destroyed_callback)
+      : content::WebContentsObserver(
+            content::WebContents::FromRenderFrameHost(child_rfh)),
+        child_rfh_(child_rfh),
+        permissions_(permissions.begin(), permissions.end()),
+        rfh_destroyed_callback_(rfh_destroyed_callback) {}
+
+  ~DelegatedForChild() override {}
+
+  bool HasPermission(const content::PermissionType& permission) {
+    return permissions_.count(permission) == 1;
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DelegatedForChild);
+
+  void ClearPermissions(content::RenderFrameHost* render_frame_host) {
+    if (render_frame_host == child_rfh_)
+      rfh_destroyed_callback_.Run(render_frame_host);  // Will delete |this|.
+  }
+
+  // WebContentsObserver
+  void RenderFrameHostChanged(content::RenderFrameHost* old_host,
+                              content::RenderFrameHost* new_host) override {
+    ClearPermissions(old_host);
+  }
+
+  void FrameDeleted(content::RenderFrameHost* render_frame_host) override {
+    ClearPermissions(render_frame_host);
+  }
+
+  void DidNavigateAnyFrame(
+      content::RenderFrameHost* render_frame_host,
+      const content::LoadCommittedDetails& details,
+      const content::FrameNavigateParams& params) override {
+    ClearPermissions(render_frame_host);
+  }
+
+  content::RenderFrameHost* child_rfh_;
+
+  std::unordered_set<content::PermissionType, PermissionTypeHash> permissions_;
+
+  base::Callback<void(content::RenderFrameHost*)> rfh_destroyed_callback_;
+};
+
+DelegationTracker::DelegationTracker() {}
+
+DelegationTracker::~DelegationTracker() {}
+
+void DelegationTracker::SetDelegatedPermissions(
+    content::RenderFrameHost* child_rfh,
+    const std::vector<content::PermissionType>& permissions) {
+  DCHECK(child_rfh && child_rfh->GetParent());
+  delegated_permissions_[child_rfh] = base::WrapUnique(new DelegatedForChild(
+      child_rfh, permissions,
+      base::Bind(&DelegationTracker::RenderFrameHostChanged,
+                 base::Unretained(this))));
+}
+
+bool DelegationTracker::IsGranted(content::RenderFrameHost* requesting_rfh,
+                                  const content::PermissionType& permission) {
+  content::RenderFrameHost* child_rfh = requesting_rfh;
+  while (child_rfh->GetParent()) {
+    // Parents with unique origins can't delegate permission.
+    url::Origin parent_origin =
+        child_rfh->GetParent()->GetLastCommittedOrigin();
+    if (parent_origin.unique())
+      return false;
+
+    if (!child_rfh->GetLastCommittedOrigin().IsSameOriginWith(parent_origin)) {
+      const auto& it = delegated_permissions_.find(child_rfh);
+      if (it == delegated_permissions_.end())
+        return false;
+      if (!it->second->HasPermission(permission))
+        return false;
+    }
+    child_rfh = child_rfh->GetParent();
+  }
+  return true;
+}
+
+void DelegationTracker::RenderFrameHostChanged(content::RenderFrameHost* rfh) {
+  delegated_permissions_.erase(rfh);
+}