Implement OES_texture_float_linear and OES_texture_half_float_linear extensions in WebGL.

Source/core/platform/graphics/Extensions3D.h

 /*
  * Copyright (C) 2011 Google 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
@@ skipping 34 matching lines @@
     ~Extensions3D();
 
     // Supported extensions:
     //   GL_EXT_texture_format_BGRA8888
     //   GL_EXT_read_format_bgra
     //   GL_ARB_robustness
     //   GL_ARB_texture_non_power_of_two / GL_OES_texture_npot
     //   GL_EXT_packed_depth_stencil / GL_OES_packed_depth_stencil
     //   GL_ANGLE_framebuffer_blit / GL_ANGLE_framebuffer_multisample
     //   GL_OES_texture_float
+    //   GL_OES_texture_float_linear
     //   GL_OES_texture_half_float
+    //   GL_OES_texture_half_float_linear
     //   GL_OES_standard_derivatives
     //   GL_OES_rgb8_rgba8
     //   GL_OES_vertex_array_object
     //   GL_OES_element_index_uint
     //   GL_ANGLE_translated_shader_source
     //   GL_ARB_texture_rectangle (only the subset required to
     //     implement IOSurface binding; it's recommended to support
     //     this only on Mac OS X to limit the amount of code dependent
     //     on this extension)
     //   GL_EXT_texture_compression_dxt1
@@ skipping 266 matching lines @@
     friend class GraphicsContext3DPrivate;
     explicit Extensions3D(GraphicsContext3DPrivate*);
 
     // Weak pointer back to GraphicsContext3DPrivate
     GraphicsContext3DPrivate* m_private;
 };
 
 } // namespace WebCore
 
 #endif // Extensions3D_h