[ABANDONED] [WIP] Refactor SafeBrowsingResourceThrottle in preparation for WebSocket

components/safe_browsing/request_checker.h

Index: components/safe_browsing/request_checker.h
diff --git a/components/safe_browsing/request_checker.h b/components/safe_browsing/request_checker.h
new file mode 100644
index 0000000000000000000000000000000000000000..3e594c9824f427a738befdd4818285cc04d6f328
--- /dev/null
+++ b/components/safe_browsing/request_checker.h
@@ -0,0 +1,196 @@
+// Copyright 2017 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 COMPONENTS_SAFE_BROWSING_REQUEST_CHECKER_H_
+#define COMPONENTS_SAFE_BROWSING_REQUEST_CHECKER_H_
+
+#include <vector>
+
+#include "base/callback_forward.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
+#include "base/timer/timer.h"
+#include "components/safe_browsing_db/database_manager.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/common/resource_type.h"
+#include "net/log/net_log_event_type.h"
+#include "net/log/net_log_with_source.h"
+#include "url/gurl.h"
+
+namespace content {
+class WebContents;
+}
+
+namespace net {
+class URLRequest;
+}
+
+namespace security_interstitials {
+struct UnsafeResource;
+}
+
+namespace safe_browsing {
+
+class BaseUIManager;
+class ScopedTimeoutForTesting;
+
+class RequestChecker final : public SafeBrowsingDatabaseManager::Client {
+ public:
+  enum DeferDecision {
+    DEFER,                // Should wait for permission to proceed
+    PROCEED_SKIPPED,      // ResourceType is exempted from checking
+    PROCEED_SAFE,         // Checked and safe
+    PROCEED_ALWAYS_ASYNC  // Checks are always async on this platform
+  };
+
+  class Delegate {
+   public:
+    // This duplicates the definition of
+    // content::ResourceRequestInfo::WebContentsGetter to avoid having a
+    // dependency on ResourceRequestInfo.
+    using WebContentsGetter = base::Callback<content::WebContents*(void)>;
+
+    Delegate() {}
+    virtual ~Delegate() {}
+    virtual void MaybeDestroyPrerenderContents(
+        const WebContentsGetter& web_contents_getter) = 0;
+    virtual WebContentsGetter GetWebContentsGetterForRequest(
+        const net::URLRequest* request) const = 0;
+    virtual void StartDisplayingBlockingPage(
+        const security_interstitials::UnsafeResource& resource,
+        scoped_refptr<BaseUIManager> ui_manager) = 0;
+    virtual void CancelResourceLoad() = 0;
+    virtual void ResumeResourceRequest() = 0;
+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(Delegate);
+  };
+
+  RequestChecker(const net::URLRequest* request,
+                 content::ResourceType resource_type,
+                 scoped_refptr<SafeBrowsingDatabaseManager> database_manager,
+                 scoped_refptr<BaseUIManager> ui_manager,
+                 Delegate* delegate);
+  ~RequestChecker() final;
+
+  // Should be called once to start checking the URL that was passed to the
+  // constructor.
+  DeferDecision CheckNewRequest();
+
+  // Can be called 0 or more times. Must not be called before CheckNewRequest().
+  // If the previous call to CheckNewRequest() or CheckRedirect() returned
+  // DEFER, must not be called until Delegate::ResumeResourceRequest() has been
+  // called.
+  DeferDecision CheckRedirect(const GURL& new_url);
+
+  // Should be called once. Must not be called before
+  // CheckNewRequest(). CheckRedirect() must not be called after
+  // ShouldDeferResponse(). As with CheckRedirect(), if the previous call to
+  // CheckNewRequest() or CheckRedirect() returned DEFER, ShouldDeferResponse()
+  // must not be called until Delegate::ResumeResourceRequest() has been called.
+  DeferDecision ShouldDeferResponse();
+
+  // SafeBrowsingDatabaseManager::Client implementation (called on IO thread):
+  void OnCheckBrowseUrlResult(const GURL& url,
+                              SBThreatType threat_type,
+                              const ThreatMetadata& metadata) final;
+
+ private:
+  // Describes what phase of the check a throttle is in.
+  enum State {
+    // Haven't started checking or checking is complete. Not deferred.
+    STATE_NONE,
+    // We have one outstanding URL-check. Could be deferred.
+    STATE_CHECKING_URL,
+    // We're displaying a blocking page. Could be deferred.
+    STATE_DISPLAYING_BLOCKING_PAGE,
+  };
+
+  // Describes what stage of the request got paused by the check.
+  enum DeferState {
+    DEFERRED_NONE,
+    DEFERRED_START,
+    DEFERRED_REDIRECT,
+    DEFERRED_UNCHECKED_REDIRECT,  // unchecked_redirect_url_ is populated.
+    DEFERRED_PROCESSING,
+  };
+
+  void OnBlockingPageComplete(bool proceed);
+
+  // Starts running |url| through the safe browsing check. If it returns DEFER
+  // then one of the Delegate methods will be called asynchronously. If one
+  // PROCEED_SKIPPED or PROCEED_SAFE is returned then it will take no further
+  // action. Never returns PROCEED_ALWAYS_ASYNC.
+  DeferDecision CheckUrl(const GURL& url);
+
+  // Callback for when the safe browsing check (which was initiated by
+  // StartCheckingUrl()) has taken longer than kCheckUrlTimeoutMs.
+  void OnCheckUrlTimeout();
+
+  void ResumeRequest();
+
+  // For marking network events.  |name| and |value| can be null.
+  void BeginNetLogEvent(net::NetLogEventType type,
+                        const GURL& url,
+                        const char* name,
+                        const char* value);
+  void EndNetLogEvent(net::NetLogEventType type,
+                      const char* name,
+                      const char* value);
+
+  State state_;
+  DeferState defer_state_;
+  const content::ResourceType resource_type_;
+
+  // The result of the most recent safe browsing check. Only valid to read this
+  // when state_ != STATE_CHECKING_URL.
+  safe_browsing::SBThreatType threat_type_;
+
+  // The time when we started deferring the request.
+  base::TimeTicks defer_start_time_;
+
+  const net::URLRequest* request_;
+
+  scoped_refptr<BaseUIManager> ui_manager_;
+
+  scoped_refptr<SafeBrowsingDatabaseManager> database_manager_;
+
+  // Timer to abort the safe browsing check if it takes too long.
+  base::OneShotTimer timer_;
+
+  // The redirect chain for this resource
+  std::vector<GURL> redirect_urls_;
+
+  // If in DEFERRED_UNCHECKED_REDIRECT state, this is the
+  // URL we still need to check before resuming.
+  GURL unchecked_redirect_url_;
+  GURL url_being_checked_;
+
+  net::NetLogWithSource net_log_with_source_;
+  Delegate* delegate_;
+
+  base::WeakPtrFactory<RequestChecker> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(RequestChecker);
+};
+
+// This class can be used to locally change the timeout for checks. Thread
+// hostile.
+class ScopedTimeoutForTesting {
+ public:
+  explicit ScopedTimeoutForTesting(int new_timeout_ms);
+  ScopedTimeoutForTesting(ScopedTimeoutForTesting&& rhs);
+  ~ScopedTimeoutForTesting();
+
+ private:
+  int original_timeout_ms_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedTimeoutForTesting);
+};
+
+}  // namespace safe_browsing
+
+#endif  // COMPONENTS_SAFE_BROWSING_REQUEST_CHECKER_H_