Completely removed the Extensions3D class (Take 2)

Source/core/html/canvas/OESTextureHalfFloat.cpp

Index: Source/core/html/canvas/OESTextureHalfFloat.cpp
diff --git a/Source/core/html/canvas/OESTextureHalfFloat.cpp b/Source/core/html/canvas/OESTextureHalfFloat.cpp
index 7253837aa42d7e32ebb81807e8167facd26d67fb..c7ed288324f9cad9e5d17e23f81c435374d75dd9 100644
--- a/Source/core/html/canvas/OESTextureHalfFloat.cpp
+++ b/Source/core/html/canvas/OESTextureHalfFloat.cpp
@@ -26,7 +26,6 @@
 #include "config.h"
 
 #include "core/html/canvas/OESTextureHalfFloat.h"
-#include "platform/graphics/Extensions3D.h"
 
 namespace WebCore {
 
@@ -34,7 +33,7 @@ OESTextureHalfFloat::OESTextureHalfFloat(WebGLRenderingContext* context)
     : WebGLExtension(context)
 {
     ScriptWrappable::init(this);
-    context->graphicsContext3D()->extensions()->ensureEnabled("GL_OES_texture_half_float");
+    context->graphicsContext3D()->ensureExtensionEnabled("GL_OES_texture_half_float");
 }
 
 OESTextureHalfFloat::~OESTextureHalfFloat()
@@ -53,8 +52,7 @@ PassRefPtr<OESTextureHalfFloat> OESTextureHalfFloat::create(WebGLRenderingContex
 
 bool OESTextureHalfFloat::supported(WebGLRenderingContext* context)
 {
-    Extensions3D* extensions = context->graphicsContext3D()->extensions();
-    return extensions->supports("GL_OES_texture_half_float");
+    return context->graphicsContext3D()->supportsExtension("GL_OES_texture_half_float");
 }
 
 const char* OESTextureHalfFloat::extensionName()