Use GL_chromium_color_buffer_float extensions

Source/core/html/canvas/WebGLRenderingContext.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 662 matching lines @@
     WebGLGetInfo getWebGLIntArrayParameter(GLenum);
 
     // Clear the backbuffer if it was composited since the last operation.
     // clearMask is set to the bitfield of any clear that would happen anyway at this time
     // and the function returns true if that clear is now unnecessary.
     bool clearIfComposited(GLbitfield clearMask = 0);
 
     // Helper to restore state that clearing the framebuffer may destroy.
     void restoreStateAfterClear();
 
+    // Convert texture internal format.
+    GLenum convertTexInternalFormat(GLenum internalformat, GLenum type);
+
     void texImage2DBase(GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type, const void* pixels, ExceptionState&);
     void texImage2DImpl(GLenum target, GLint level, GLenum internalformat, GLenum format, GLenum type, Image*, GraphicsContext3D::ImageHtmlDomSource, bool flipY, bool premultiplyAlpha, ExceptionState&);
     void texSubImage2DBase(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLenum type, const void* pixels, ExceptionState&);
     void texSubImage2DImpl(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLenum format, GLenum type, Image*, GraphicsContext3D::ImageHtmlDomSource, bool flipY, bool premultiplyAlpha, ExceptionState&);
 
     void handleTextureCompleteness(const char*, bool);
     void createFallbackBlackTextures1x1();
 
     // Helper function for copyTex{Sub}Image, check whether the internalformat
     // and the color buffer format of the current bound framebuffer combination
@@ skipping 229 matching lines @@
     // If the vector is empty, return the maximum allowed active context number.
     static size_t oldestContextIndex();
     static IntSize oldestContextSize();
 };
 
 DEFINE_TYPE_CASTS(WebGLRenderingContext, CanvasRenderingContext, context, context->is3d(), context.is3d());
 
 } // namespace WebCore
 
 #endif