Create Content API around HostZoomMap.

content/public/browser/host_zoom_map.h

+// Copyright (c) 2012 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_PUBLIC_BROWSER_HOST_ZOOM_MAP_H_
+#define CONTENT_PUBLIC_BROWSER_HOST_ZOOM_MAP_H_
+#pragma once
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "content/common/content_export.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace content {
+
+// Maps hostnames to custom zoom levels.  Written on the UI thread and read on
+// any thread.  One instance per browser context. Must be created on the UI
+// thread, and it'll delete itself on the UI thread as well.
+class HostZoomMap
+    : public base::RefCountedThreadSafe<
+          HostZoomMap, content::BrowserThread::DeleteOnUIThread> {
+ public:
+  CONTENT_EXPORT static HostZoomMap* Create();
+
+  // Copy the zoom levels from the given map. Can only be called on the UI
+  // thread.
+  virtual void CopyFrom(HostZoomMap* copy) = 0;
+
+  // Returns the zoom level for the host or spec for a given url. The zoom
+  // level is determined by the host portion of the URL, or (in the absence of
+  // a host) the complete spec of the URL. In most cases, there is no custom
+  // zoom level, and this returns the user's default zoom level.  Otherwise,
+  // returns the saved zoom level, which may be positive (to zoom in) or
+  // negative (to zoom out).
+  //
+  // This may be called on any thread.
+  virtual double GetZoomLevel(const std::string& host) const = 0;
+
+  // Sets the zoom level for the host or spec for a given url to |level|.  If
+  // the level matches the current default zoom level, the host is erased
+  // from the saved preferences; otherwise the new value is written out.
+  //
+  // This should only be called on the UI thread.
+  virtual void SetZoomLevel(std::string host, double level) = 0;
+
+  // Get/Set the default zoom level for pages that don't override it.
+  virtual double GetDefaultZoomLevel() const = 0;
+  virtual void SetDefaultZoomLevel(double level) = 0;;
+
+ protected:
+  virtual ~HostZoomMap() {}
+
+ private:
+  friend class base::RefCountedThreadSafe<
+      HostZoomMap, content::BrowserThread::DeleteOnUIThread>;
+  friend struct content::BrowserThread::DeleteOnThread<
+      content::BrowserThread::UI>;
+  friend class base::DeleteHelper<HostZoomMap>;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_HOST_ZOOM_MAP_H_