Pass distillability updates from renderer to browser

components/dom_distiller/content/browser/distillability_driver.h

Index: components/dom_distiller/content/browser/distillability_driver.h
diff --git a/components/dom_distiller/content/browser/distillability_driver.h b/components/dom_distiller/content/browser/distillability_driver.h
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+++ b/components/dom_distiller/content/browser/distillability_driver.h
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+// Copyright 2015 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_DOM_DISTILLER_CONTENT_BROWSER_DISTILLIBILITY_DRIVER_H_
+#define COMPONENTS_DOM_DISTILLER_CONTENT_BROWSER_DISTILLIBILITY_DRIVER_H_
+
+#include "base/macros.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "content/public/browser/web_contents_user_data.h"
+
+namespace dom_distiller {
+
+// This is an IPC helper for determining whether a page should be distilled.
+class DistillabilityDriver
+    : public content::WebContentsObserver,
+      public content::WebContentsUserData<DistillabilityDriver> {
+ public:
+  ~DistillabilityDriver() override;
+
+  void SetDelegate(const base::Callback<void(bool, bool)>& delegate);
+
+  // content::WebContentsObserver implementation.
+  bool OnMessageReceived(const IPC::Message& message,
+                         content::RenderFrameHost* rfh) override;
+  void RenderProcessGone(base::TerminationStatus status) override;
+
+ private:
+  explicit DistillabilityDriver(content::WebContents* web_contents);
+  friend class content::WebContentsUserData<DistillabilityDriver>;
+
+  void OnDistillability(bool distillable, bool is_last);
+
+  // Removes the observer and clears the WebContents member.
+  void CleanUp();
+
+  base::Callback<void(bool, bool)> m_delegate_;
+
+  DISALLOW_COPY_AND_ASSIGN(DistillabilityDriver);
+};
+
+}  // namespace dom_distiller
+
+#endif  // COMPONENTS_DOM_DISTILLER_CONTENT_BROWSER_DISTILLIBILITY_DRIVER_H_