Remove usage of HostZoomMap from c/b/loader via ReadyToCommitNavigation

content/browser/host_zoom_map_observer.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_HOST_ZOOM_MAP_OBSERVER_H_
+#define CONTENT_BROWSER_HOST_ZOOM_MAP_OBSERVER_H_
+
+#include "content/common/host_zoom.mojom.h"
+#include "content/public/browser/web_contents_observer.h"
+
+namespace content {
+
+class RenderFrameHost;
+
+class HostZoomMapObserver : private WebContentsObserver {
+ public:
+  explicit HostZoomMapObserver(WebContents* web_contents);
+  ~HostZoomMapObserver() override;
+
+ private:
+  // WebContentsObserver implementation:
+  void ReadyToCommitNavigation(NavigationHandle* navigation_handle) override;
+  void RenderFrameCreated(RenderFrameHost* rfh) override;
+
+  mojom::HostZoomAssociatedPtr host_zoom_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_HOST_ZOOM_MAP_OBSERVER_H_