update getFramebufferAttachmentParameter for WebGL 2

Source/core/html/canvas/WebGLRenderingContextBase.cpp

Index: Source/core/html/canvas/WebGLRenderingContextBase.cpp
diff --git a/Source/core/html/canvas/WebGLRenderingContextBase.cpp b/Source/core/html/canvas/WebGLRenderingContextBase.cpp
index bb8ca51cfa5f763d6240daec7551465316b9b35d..33c80168a01caab5d36930ff782da70574320997 100644
--- a/Source/core/html/canvas/WebGLRenderingContextBase.cpp
+++ b/Source/core/html/canvas/WebGLRenderingContextBase.cpp
@@ -2287,10 +2287,10 @@ ScriptValue WebGLRenderingContextBase::getFramebufferAttachmentParameter(ScriptS
                 return WebGLAny(scriptState, value);
             }
         case GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING_EXT:
-            if (extensionEnabled(EXTsRGBName) || isWebGL2OrHigher()) {
+            if (extensionEnabled(EXTsRGBName)) {
                 GLint value = 0;
                 webContext()->getFramebufferAttachmentParameteriv(target, attachment, pname, &value);
-                return WebGLAny(scriptState, value);
+                return WebGLAny(scriptState, static_cast<unsigned>(value));
             }
             synthesizeGLError(GL_INVALID_ENUM, "getFramebufferAttachmentParameter", "invalid parameter name for renderbuffer attachment");
             return ScriptValue::createNull(scriptState);