[Oilpan] Migrate classes under module/webgl onto oilpan heap

Source/modules/webgl/EXTsRGB.h

Index: Source/modules/webgl/EXTsRGB.h
diff --git a/Source/modules/webgl/EXTsRGB.h b/Source/modules/webgl/EXTsRGB.h
index e3ed2fd70a2d5884ba88f55db73df9e6ca67c4fe..89a729c4ea6a157228003def184219f090d60ccc 100644
--- a/Source/modules/webgl/EXTsRGB.h
+++ b/Source/modules/webgl/EXTsRGB.h
@@ -6,14 +6,13 @@
 #define EXTsRGB_h
 
 #include "modules/webgl/WebGLExtension.h"
-#include "wtf/PassRefPtr.h"
 
 namespace blink {
 
 class EXTsRGB final : public WebGLExtension {
     DEFINE_WRAPPERTYPEINFO();
 public:
-    static PassRefPtrWillBeRawPtr<EXTsRGB> create(WebGLRenderingContextBase*);
+    static EXTsRGB* create(WebGLRenderingContextBase*);
     static bool supported(WebGLRenderingContextBase*);
     static const char* extensionName();