[subresource_filter] SB throttle can send multiple speculative requests.

content/public/test/cancelling_navigation_throttle.cc

Index: content/public/test/cancelling_navigation_throttle.cc
diff --git a/content/public/test/cancelling_navigation_throttle.cc b/content/public/test/cancelling_navigation_throttle.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4a3b7713d5cc041dff9ee13a8c3fe1cbd347d48e
--- /dev/null
+++ b/content/public/test/cancelling_navigation_throttle.cc
@@ -0,0 +1,59 @@
+// 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.
+
+#include "content/public/test/cancelling_navigation_throttle.h"
+
+#include "base/bind.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/navigation_handle.h"
+
+namespace content {
+
+CancellingNavigationThrottle::CancellingNavigationThrottle(
+    NavigationHandle* handle,
+    CancelTime cancel_time,
+    ResultSynchrony sync)
+    : NavigationThrottle(handle),
+      cancel_time_(cancel_time),
+      sync_(sync),
+      weak_ptr_factory_(this) {}
+
+CancellingNavigationThrottle::~CancellingNavigationThrottle() {}
+
+NavigationThrottle::ThrottleCheckResult
+CancellingNavigationThrottle::WillStartRequest() {
+  return ProcessState(cancel_time_ == WILL_START_REQUEST);
+}
+
+NavigationThrottle::ThrottleCheckResult
+CancellingNavigationThrottle::WillRedirectRequest() {
+  return ProcessState(cancel_time_ == WILL_REDIRECT_REQUEST);
+}
+
+NavigationThrottle::ThrottleCheckResult
+CancellingNavigationThrottle::WillProcessResponse() {
+  return ProcessState(cancel_time_ == WILL_PROCESS_RESPONSE);
+}
+
+NavigationThrottle::ThrottleCheckResult
+CancellingNavigationThrottle::ProcessState(bool should_cancel) {
+  if (sync_ == ASYNCHRONOUS) {
+    BrowserThread::PostTask(
+        BrowserThread::UI, FROM_HERE,
+        base::Bind(&CancellingNavigationThrottle::MaybeCancel,
+                   weak_ptr_factory_.GetWeakPtr(), should_cancel));
+    return NavigationThrottle::DEFER;
+  }
+  return should_cancel ? NavigationThrottle::CANCEL
+                       : NavigationThrottle::PROCEED;
+}
+
+void CancellingNavigationThrottle::MaybeCancel(bool cancel) {
+  if (cancel)
+    navigation_handle()->CancelDeferredNavigation(NavigationThrottle::CANCEL);
+  else
+    navigation_handle()->Resume();
+}
+
+}  // namespace content