Make WebGLRenderingContext.getAttachedShaders() return type nullable

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 168 matching lines @@
     void enableVertexAttribArray(GLuint index);
     void finish();
     void flush();
     void framebufferRenderbuffer(GLenum target, GLenum attachment, GLenum renderbuffertarget, WebGLRenderbuffer*);
     void framebufferTexture2D(GLenum target, GLenum attachment, GLenum textarget, WebGLTexture*, GLint level);
     void frontFace(GLenum mode);
     void generateMipmap(GLenum target);
 
     PassRefPtr<WebGLActiveInfo> getActiveAttrib(WebGLProgram*, GLuint index);
     PassRefPtr<WebGLActiveInfo> getActiveUniform(WebGLProgram*, GLuint index);
-    bool getAttachedShaders(WebGLProgram*, Vector<RefPtr<WebGLShader> >&);
+    Nullable<Vector<RefPtr<WebGLShader> > > getAttachedShaders(WebGLProgram*);
     GLint getAttribLocation(WebGLProgram*, const String& name);
     WebGLGetInfo getBufferParameter(GLenum target, GLenum pname);
     PassRefPtr<WebGLContextAttributes> getContextAttributes();
     GLenum getError();
     PassRefPtr<WebGLExtension> getExtension(const String& name);
     WebGLGetInfo getFramebufferAttachmentParameter(GLenum target, GLenum attachment, GLenum pname);
     WebGLGetInfo getParameter(GLenum pname);
     WebGLGetInfo getProgramParameter(WebGLProgram*, GLenum pname);
     String getProgramInfoLog(WebGLProgram*);
     WebGLGetInfo getRenderbufferParameter(GLenum target, GLenum pname);
@@ skipping 703 matching lines @@
     // If the vector is empty, return the maximum allowed active context number.
     static size_t oldestContextIndex();
     static IntSize oldestContextSize();
 };
 
 DEFINE_TYPE_CASTS(WebGLRenderingContextBase, CanvasRenderingContext, context, context->is3d(), context.is3d());
 
 } // namespace WebCore
 
 #endif // WebGLRenderingContextBase_h