Refactor to move chrome_page_zoom functions to components/ui/zoom.

components/ui/zoom/page_zoom.h

+// 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_UI_ZOOM_PAGE_ZOOM_H_
+#define COMPONENTS_UI_ZOOM_PAGE_ZOOM_H_
+
+#include <vector>
+
+#include "base/macros.h"
+#include "content/public/common/page_zoom.h"
+
+namespace content {
+class WebContents;
+}
+
+namespace ui_zoom {
+
+// This class provides a means of zooming pages according to a predetermined
+// set of zoom levels/factors. In future, the static methods in this class
+// can be made non-static, with PresetZoomX() being virtual, to allow clients
+// to create custom sets of zoom levels.
+class PageZoom {
+ public:
+  // Return a sorted vector of zoom factors. The vector will consist of preset
+  // values along with a custom value (if the custom value is not already
+  // represented.)
+  static std::vector<double> PresetZoomFactors(double custom_factor);
+
+  // Return a sorted vector of zoom levels. The vector will consist of preset
+  // values along with a custom value (if the custom value is not already
+  // represented.)
+  static std::vector<double> PresetZoomLevels(double custom_level);
+
+  // Adjusts the zoom level of |web_contents|.
+  static void Zoom(content::WebContents* web_contents, content::PageZoom zoom);
+
+ private:
+  // We don't expect (currently) to create instances of this class.
+  PageZoom() {}
+  DISALLOW_COPY_AND_ASSIGN(PageZoom);
+};
+
+}  // namespace ui_zoom
+
+#endif  // COMPONENTS_UI_ZOOM_PAGE_ZOOM_H_