[TooManyTabs] Add TabNavigationThrottle

chrome/browser/resource_coordinator/background_tab_navigation_throttle.h

Index: chrome/browser/resource_coordinator/background_tab_navigation_throttle.h
diff --git a/chrome/browser/resource_coordinator/background_tab_navigation_throttle.h b/chrome/browser/resource_coordinator/background_tab_navigation_throttle.h
new file mode 100644
index 0000000000000000000000000000000000000000..029ae21c2bc888f5e26e2d0b2ddc786024a46535
--- /dev/null
+++ b/chrome/browser/resource_coordinator/background_tab_navigation_throttle.h
@@ -0,0 +1,36 @@
+// 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 CHROME_BROWSER_RESOURCE_COORDINATOR_BACKGROUND_TAB_NAVIGATION_THROTTLE_H_
+#define CHROME_BROWSER_RESOURCE_COORDINATOR_BACKGROUND_TAB_NAVIGATION_THROTTLE_H_
+
+#include <memory>
+
+#include "base/macros.h"
+#include "content/public/browser/navigation_throttle.h"
+
+namespace resource_coordinator {
+
+// BackgroundTabNavigationThrottle plumbs navigation information to TabManager
+// and enables TabManager to delay navigation for background tabs.

[Charlie Reis, 2017/07/07 22:07:56]

Might want to mention here as well that it's not used on Android?

[Zhen Wang, 2017/07/10 17:21:54]

Done.

+class BackgroundTabNavigationThrottle : public content::NavigationThrottle {
+ public:
+  static std::unique_ptr<BackgroundTabNavigationThrottle>
+  MaybeCreateThrottleFor(content::NavigationHandle* navigation_handle);
+
+  explicit BackgroundTabNavigationThrottle(
+      content::NavigationHandle* navigation_handle);
+  ~BackgroundTabNavigationThrottle() override;
+
+  // content::NavigationThrottle implementation
+  const char* GetNameForLogging() override;
+  content::NavigationThrottle::ThrottleCheckResult WillStartRequest() override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(BackgroundTabNavigationThrottle);
+};
+
+}  // namespace resource_coordinator
+
+#endif  // CHROME_BROWSER_RESOURCE_COORDINATOR_BACKGROUND_TAB_NAVIGATION_THROTTLE_H_