Moved the majority of WebGL functionality into WebGLRenderingContextBase

Source/core/html/canvas/WebGLCompressedTextureATC.cpp

Index: Source/core/html/canvas/WebGLCompressedTextureATC.cpp
diff --git a/Source/core/html/canvas/WebGLCompressedTextureATC.cpp b/Source/core/html/canvas/WebGLCompressedTextureATC.cpp
index 9df4b36a06d2003a81d35985b2388517c5dc218e..6b362440913061ea682d5f4c4c43349b4f2ac7f6 100644
--- a/Source/core/html/canvas/WebGLCompressedTextureATC.cpp
+++ b/Source/core/html/canvas/WebGLCompressedTextureATC.cpp
@@ -31,7 +31,7 @@
 
 namespace WebCore {
 
-WebGLCompressedTextureATC::WebGLCompressedTextureATC(WebGLRenderingContext* context)
+WebGLCompressedTextureATC::WebGLCompressedTextureATC(WebGLRenderingContextBase* context)
     : WebGLExtension(context)
 {
     ScriptWrappable::init(this);
@@ -49,12 +49,12 @@ WebGLExtension::ExtensionName WebGLCompressedTextureATC::getName() const
     return WebGLCompressedTextureATCName;
 }
 
-PassRefPtr<WebGLCompressedTextureATC> WebGLCompressedTextureATC::create(WebGLRenderingContext* context)
+PassRefPtr<WebGLCompressedTextureATC> WebGLCompressedTextureATC::create(WebGLRenderingContextBase* context)
 {
     return adoptRef(new WebGLCompressedTextureATC(context));
 }
 
-bool WebGLCompressedTextureATC::supported(WebGLRenderingContext* context)
+bool WebGLCompressedTextureATC::supported(WebGLRenderingContextBase* context)
 {
     Extensions3D* extensions = context->graphicsContext3D()->getExtensions();
     return extensions->supports("GL_AMD_compressed_ATC_texture");