WebGL: add targets for WebGL 2 when check FBO targets

Source/core/html/canvas/WebGL2RenderingContextBase.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/html/canvas/WebGL2RenderingContextBase.h"
 
 #include "bindings/core/v8/WebGLAny.h"
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLImageElement.h"
@@ skipping 1443 matching lines @@
         // FIXME: Some of these ES3 buffer targets may require additional state tracking.
         break;
     default:
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid target");
         return false;
     }
 
     return true;
 }
 
+bool WebGL2RenderingContextBase::validateFramebufferTarget(GLenum target)
+{
+    switch (target) {
+    case GL_FRAMEBUFFER:
+    case GL_READ_FRAMEBUFFER:
+    case GL_DRAW_FRAMEBUFFER:
+        return true;
+    default:
+        return false;
+    }
+}
+
 DEFINE_TRACE(WebGL2RenderingContextBase)
 {
     visitor->trace(m_readFramebufferBinding);
     WebGLRenderingContextBase::trace(visitor);
 }
 
 } // namespace blink