First experimental implementation of the Clear-Site-Data header

content/browser/browsing_data/clear_site_data_throttle.h

+// 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.
+
+#ifndef CONTENT_BROWSER_BROWSING_DATA_CLEAR_SITE_DATA_THROTTLE_H_
+#define CONTENT_BROWSER_BROWSING_DATA_CLEAR_SITE_DATA_THROTTLE_H_
+
+#include <memory>
+#include <vector>
+
+#include "base/gtest_prod_util.h"
+#include "base/macros.h"
+#include "base/values.h"
+#include "content/public/browser/navigation_throttle.h"
+#include "content/public/browser/resource_request_info.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "content/public/common/console_message_level.h"
+#include "url/gurl.h"
+
+class Profile;
+
+namespace content {
+
+class NavigationHandle;
+
+// This throttle asynchronously executes the clearing of browsing data.
+// It does not block navigation.
+class CONTENT_EXPORT ClearSiteDataThrottle : public NavigationThrottle,

[clamy, 2016/07/26 16:48:13]

It seems very weird to me to have a class that is both a throttle and an
observer. Considering that you don't need to cancel anything, you probably just
need a WebContentsObserver (and not a NavigationThrottle). WebContentsObserver
has a method that is called on redirects (DidRedirectNavigation), so there is no
need of a throttle for that.

[msramek, 2016/07/27 15:02:53]

Done. Renamed to ClearSiteDataHeaderObserver, and no longer inheriting from
NavigationThrottle.

This really made the class itself a bit cleaner, but it looks weird in
NavigationHandleImpl, since it didn't have any such custom observers before. Are
you OK with that? Even after this change, it's still a platform
s/throttle/observer/ that is tied to a single navigation, so
NavigationHandleImpl still seems like a reasonable place to put it to.

+                                             public WebContentsObserver {
+ public:
+  struct ConsoleMessage {
+    std::string text;
+    ConsoleMessageLevel level;
+  };
+
+  static std::unique_ptr<NavigationThrottle>
+      CreateThrottleFor(NavigationHandle* handle);
+
+  ~ClearSiteDataThrottle() override;
+
+  // NavigationThrottle implementation:
+  ThrottleCheckResult WillStartRequest() override;
+  ThrottleCheckResult WillProcessResponse() override;
+  ThrottleCheckResult WillRedirectRequest() override;
+
+  // WebContentsObserver implementation:
+  void DidFinishNavigation(NavigationHandle* handle) override;
+
+ private:
+  explicit ClearSiteDataThrottle(NavigationHandle* handle);
+
+  // Scans for 'Clear-Site-Data' headers, calls ParseHeader() to parse them,
+  // and requests the actual data clearing. This is the common logic
+  // of WillProcessResponse() and WillRedirectRequest().
+  void HandleHeader();
+
+  // Parses the value of the 'Clear-Site-Data' header and outputs whether
+  // the header requests to |clear_cookies|, |clear_storage|, and |clear_cache|.
+  // The |messages| vector will be filled with messages to be output in the
+  // console. Returns true if parsing was successful.
+  bool ParseHeader(const std::string& header,
+                   bool* clear_cookies, bool* clear_storage, bool* clear_cache,
+                   std::vector<ConsoleMessage>* messages);
+
+  // Cached console messages to be output when the RenderFrameHost is ready.
+  std::vector<ConsoleMessage> messages_;
+  GURL current_url_;
+
+  FRIEND_TEST_ALL_PREFIXES(ClearSiteDataThrottleTest, ParseHeader);
+  FRIEND_TEST_ALL_PREFIXES(ClearSiteDataThrottleTest, InvalidHeader);
+
+  DISALLOW_COPY_AND_ASSIGN(ClearSiteDataThrottle);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_BROWSING_DATA_CLEAR_SITE_DATA_THROTTLE_H_