Completely removed the Extensions3D class (Take 2)

Source/core/html/canvas/OESTextureHalfFloatLinear.cpp

Index: Source/core/html/canvas/OESTextureHalfFloatLinear.cpp
diff --git a/Source/core/html/canvas/OESTextureHalfFloatLinear.cpp b/Source/core/html/canvas/OESTextureHalfFloatLinear.cpp
index c7da9bd745b4983b2103ee49ef1e0da3994536c1..3428c46345e8942405eecb7b693242261c8fb7e3 100644
--- a/Source/core/html/canvas/OESTextureHalfFloatLinear.cpp
+++ b/Source/core/html/canvas/OESTextureHalfFloatLinear.cpp
@@ -27,15 +27,13 @@
 
 #include "core/html/canvas/OESTextureHalfFloatLinear.h"
 
-#include "platform/graphics/Extensions3D.h"
-
 namespace WebCore {
 
 OESTextureHalfFloatLinear::OESTextureHalfFloatLinear(WebGLRenderingContext* context)
     : WebGLExtension(context)
 {
     ScriptWrappable::init(this);
-    context->graphicsContext3D()->extensions()->ensureEnabled("GL_OES_texture_half_float_linear");
+    context->graphicsContext3D()->ensureExtensionEnabled("GL_OES_texture_half_float_linear");
 }
 
 OESTextureHalfFloatLinear::~OESTextureHalfFloatLinear()
@@ -54,8 +52,7 @@ PassRefPtr<OESTextureHalfFloatLinear> OESTextureHalfFloatLinear::create(WebGLRen
 
 bool OESTextureHalfFloatLinear::supported(WebGLRenderingContext* context)
 {
-    Extensions3D* extensions = context->graphicsContext3D()->extensions();
-    return extensions->supports("GL_OES_texture_half_float_linear");
+    return context->graphicsContext3D()->supportsExtension("GL_OES_texture_half_float_linear");
 }
 
 const char* OESTextureHalfFloatLinear::extensionName()