Adds public API and loads Cast OSD plane implementation from shared lib

chromecast/public/cast_egl_platform.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 CHROMECAST_PUBLIC_CAST_EGL_PLATFORM_H_
 #define CHROMECAST_PUBLIC_CAST_EGL_PLATFORM_H_
 
 namespace chromecast {
 
+struct Size;
+
 // Interface representing all the hardware-specific elements of an Ozone
 // implementation for Cast.  Supply an implementation of this interface
 // to OzonePlatformCast to create a complete Ozone implementation.
 class CastEglPlatform {
  public:
-  struct Size {
-    Size(int w, int h) : width(w), height(h) {}
-    const int width;
-    const int height;
-  };
-
   typedef void* (*GLGetProcAddressProc)(const char* name);
   typedef void* NativeDisplayType;
   typedef void* NativeWindowType;
 
   virtual ~CastEglPlatform() {}
 
   // Returns an array of EGL properties, which can be used in any EGL function
   // used to select a display configuration. Note that all properties should be
   // immediately followed by the corresponding desired value and array should be
   // terminated with EGL_NONE. Ownership of the array is not transferred to
@@ skipping 24 matching lines @@
   // Creates/destroys an EGLNativeWindow.  There will be at most one window at a
   // time, created within a valid display type.
   virtual NativeWindowType CreateWindow(NativeDisplayType display_type,
                                         const Size& size) = 0;
   virtual void DestroyWindow(NativeWindowType window) = 0;
 };
 
 }  // namespace chromecast
 
 #endif  // CHROMECAST_PUBLIC_CAST_EGL_PLATFORM_H_