cast: support cursor rendering for tab capture

content/browser/media/capture/cursor_renderer.h

+// Copyright (c) 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 CONTENT_BROWSER_MEDIA_CAPTURE_CURSOR_RENDERER_H_
+#define CONTENT_BROWSER_MEDIA_CAPTURE_CURSOR_RENDERER_H_
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "content/common/content_export.h"
+#include "media/base/video_frame.h"
+#include "ui/gfx/native_widget_types.h"
+
+namespace content {
+
+// CursorRenderer is an interface that can be implememented to do cursor
+// rendering on a video frame.
+//
+// In order to track the cursor, the platform-specific implementation
+// will listen to mouse events.
+class CONTENT_EXPORT CursorRenderer {
+ public:
+  virtual ~CursorRenderer() {}
+
+  // Clears the cursor state being tracked. Called when there is a need to
+  // reset the state.
+  virtual void Clear() = 0;
+
+  // Takes a snapshot of the current cursor state and determines whether
+  // the cursor will be rendered, which cursor image to render, and at what
+  // location within |region_in_frame| to render it. Returns true if cursor
+  // needs to be rendered.
+  virtual bool SnapshotCursorState(const gfx::Rect& region_in_frame) = 0;
+
+  // Renders cursor on the |target| video frame.
+  virtual void RenderOnVideoFrame(
+      const scoped_refptr<media::VideoFrame>& target) const = 0;
+
+  // Returns a weak pointer.
+  virtual base::WeakPtr<CursorRenderer> GetWeakPtr() = 0;
+
+ protected:
+  enum {
+    // Minium movement before cursor is rendered on frame.
+    MIN_MOVEMENT_PIXELS = 15,
+    // Maximum idle time allowed before we stop rendering the cursor
+    // on frame.
+    MAX_IDLE_TIME_SECONDS = 2
+  };
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_MEDIA_CAPTURE_CURSOR_RENDERER_H_