Add OES_texture_half_float extension support in WebGL.

Source/core/platform/graphics/GraphicsContext3D.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 503 matching lines @@
 
 
     // Attempt to enumerate all possible native image formats to
     // reduce the amount of temporary allocations during texture
     // uploading. This enum must be public because it is accessed
     // by non-member functions.
     enum DataFormat {
         DataFormatRGBA8 = 0,
         DataFormatRGBA16Little,
         DataFormatRGBA16Big,
+        DataFormatRGBA16F,
         DataFormatRGBA32F,
         DataFormatRGB8,
         DataFormatRGB16Little,
         DataFormatRGB16Big,
+        DataFormatRGB16F,
         DataFormatRGB32F,
         DataFormatBGR8,
         DataFormatBGRA8,
         DataFormatBGRA16Little,
         DataFormatBGRA16Big,
         DataFormatARGB8,
         DataFormatARGB16Little,
         DataFormatARGB16Big,
         DataFormatABGR8,
         DataFormatRGBA5551,
         DataFormatRGBA4444,
         DataFormatRGB565,
         DataFormatR8,
         DataFormatR16Little,
         DataFormatR16Big,
+        DataFormatR16F,
         DataFormatR32F,
         DataFormatRA8,
         DataFormatRA16Little,
         DataFormatRA16Big,
+        DataFormatRA16F,
         DataFormatRA32F,
         DataFormatAR8,
         DataFormatAR16Little,
         DataFormatAR16Big,
         DataFormatA8,
         DataFormatA16Little,
         DataFormatA16Big,
+        DataFormatA16F,
         DataFormatA32F,
         DataFormatNumFormats
     };
 
     // Check if the format is one of the formats from the ImageData or DOM elements.
     // The formats from ImageData is always RGBA8.
     // The formats from DOM elements vary with Graphics ports. It can only be RGBA8 or BGRA8 for non-CG port while a little more for CG port.
     static ALWAYS_INLINE bool srcFormatComeFromDOMElementOrImageData(DataFormat SrcFormat)
     {
     return SrcFormat == DataFormatBGRA8 || SrcFormat == DataFormatRGBA8;
@@ skipping 315 matching lines @@
     // Errors raised by synthesizeGLError().
     ListHashSet<GC3Denum> m_syntheticErrors;
 
     friend class GraphicsContext3DPrivate;
     OwnPtr<GraphicsContext3DPrivate> m_private;
 };
 
 } // namespace WebCore
 
 #endif // GraphicsContext3D_h