WebGL 2: validate read buffer attachment when reading from FBO

Source/core/html/canvas/WebGLRenderingContextBase.h

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 844 matching lines @@
     bool validateCompressedTexFormat(GLenum format);
 
     // Helper function to validate compressed texture dimensions are valid for
     // the given format.
     bool validateCompressedTexDimensions(const char* functionName, TexImageFunctionType, GLenum target, GLint level, GLsizei width, GLsizei height, GLenum format);
 
     // Helper function to validate compressed texture dimensions are valid for
     // the given format.
     bool validateCompressedTexSubDimensions(const char* functionName, GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, WebGLTexture*);
 
+    // Helper function to validate that the image is attached to read buffer
+    // when reading from FBO (readPixels/copyTexImage2D/copyTexSubImage2D).
+    bool validateReadBufferAttachment(const char* functionName, const WebGLFramebuffer* readFramebufferBinding);
+
     // Helper function to validate mode for draw{Arrays/Elements}.
     bool validateDrawMode(const char* functionName, GLenum);
 
     // Helper function to validate if front/back stencilMask and stencilFunc settings are the same.
     bool validateStencilSettings(const char* functionName);
 
     // Helper function to validate stencil or depth func.
     bool validateStencilOrDepthFunc(const char* functionName, GLenum);
 
     // Helper function for texParameterf and texParameteri.
@@ skipping 140 matching lines @@
     static IntSize oldestContextSize();
 };
 
 DEFINE_TYPE_CASTS(WebGLRenderingContextBase, CanvasRenderingContext, context, context->is3d(), context.is3d());
 
 } // namespace blink
 
 WTF_ALLOW_MOVE_INIT_AND_COMPARE_WITH_MEM_FUNCTIONS(blink::WebGLRenderingContextBase::TextureUnitState);
 
 #endif // WebGLRenderingContextBase_h