Fix transform feedback bugs

third_party/WebKit/Source/modules/webgl/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 "modules/webgl/WebGL2RenderingContextBase.h"
 
 #include "bindings/modules/v8/WebGLAny.h"
 #include "core/frame/ImageBitmap.h"
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLImageElement.h"
@@ skipping 1988 matching lines @@
 {
     if (isContextLost())
         return nullptr;
     WebGLTransformFeedback* o = WebGLTransformFeedback::create(this);
     addSharedObject(o);
     return o;
 }
 
 void WebGL2RenderingContextBase::deleteTransformFeedback(WebGLTransformFeedback* feedback)
 {
+    if (transformFeedbackActive()) {
+        synthesizeGLError(GL_INVALID_OPERATION, "deleteTransformFeedback", "transform feedback is active");
+        return;
+    }
     if (feedback == m_transformFeedbackBinding)
         m_transformFeedbackBinding = nullptr;
 
     deleteObject(feedback);
 }
 
 GLboolean WebGL2RenderingContextBase::isTransformFeedback(WebGLTransformFeedback* feedback)
 {
     if (isContextLost() || !feedback)
         return 0;
@@ skipping 1414 matching lines @@
     params.alignment = m_unpackAlignment;
     params.rowLength = m_unpackRowLength;
     params.imageHeight = m_unpackImageHeight;
     params.skipPixels = m_unpackSkipPixels;
     params.skipRows = m_unpackSkipRows;
     params.skipImages = m_unpackSkipImages;
     return params;
 }
 
 } // namespace blink