Move optional.h to webrtc/api/

webrtc/sdk/objc/Framework/Classes/Video/RTCDefaultShader.mm

 /*
  *  Copyright 2017 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #import "RTCDefaultShader.h"
 
 #if TARGET_OS_IPHONE
 #import <OpenGLES/ES3/gl.h>
 #else
 #import <OpenGL/gl3.h>
 #endif
 
 #import "RTCOpenGLDefines.h"
 #import "RTCShader.h"
 #import "WebRTC/RTCLogging.h"
 
-#include "webrtc/rtc_base/optional.h"
+#include "webrtc/api/optional.h"
 
 static const int kYTextureUnit = 0;
 static const int kUTextureUnit = 1;
 static const int kVTextureUnit = 2;
 static const int kUvTextureUnit = 1;
 
 // Fragment shader converts YUV values from input textures into a final RGB
 // pixel. The conversion formula is from http://www.fourcc.org/fccyvrgb.php.
 static const char kI420FragmentShaderSource[] =
   SHADER_VERSION
@@ skipping 164 matching lines @@
   glActiveTexture(static_cast<GLenum>(GL_TEXTURE0 + kYTextureUnit));
   glBindTexture(GL_TEXTURE_2D, yPlane);
 
   glActiveTexture(static_cast<GLenum>(GL_TEXTURE0 + kUvTextureUnit));
   glBindTexture(GL_TEXTURE_2D, uvPlane);
 
   glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 }
 
 @end