Fix state management of transform feedback buffers.

third_party/WebKit/Source/modules/webgl/WebGLTransformFeedback.h

 // 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.
 
 #ifndef WebGLTransformFeedback_h
 #define WebGLTransformFeedback_h
 
+#include "modules/webgl/WebGLContextObject.h"
 #include "modules/webgl/WebGLProgram.h"
-#include "modules/webgl/WebGLSharedPlatform3DObject.h"
 #include "platform/wtf/PassRefPtr.h"
 
 namespace blink {
 
 class WebGL2RenderingContextBase;
+class WebGLBuffer;
 
-class WebGLTransformFeedback : public WebGLSharedPlatform3DObject {
+class WebGLTransformFeedback : public WebGLContextObject {
   DEFINE_WRAPPERTYPEINFO();
 
  public:
+  enum TFType {
+    TFTypeDefault,
+    TFTypeUser,
+  };
+
   ~WebGLTransformFeedback() override;
 
-  static WebGLTransformFeedback* Create(WebGL2RenderingContextBase*);
+  GLuint Object() const { return object_; }
+
+  static WebGLTransformFeedback* Create(WebGL2RenderingContextBase*, TFType);
+
+  bool IsDefaultObject() const { return type_ == TFTypeDefault; }
 
   GLenum GetTarget() const { return target_; }
   void SetTarget(GLenum);
 
-  bool HasEverBeenBound() const { return Object() && target_; }
+  bool HasEverBeenBound() const { return object_ && target_; }
 
   WebGLProgram* GetProgram() const { return program_; }
   void SetProgram(WebGLProgram*);
 
-  DECLARE_TRACE();
+  // This is the generic bind point for the transform feedback buffer.
+  void SetBoundTransformFeedbackBuffer(WebGLBuffer*);
+  WebGLBuffer* GetBoundTransformFeedbackBuffer() const;
+
+  // These are the indexed bind points for transform feedback buffers.
+  // Returns false if index is out of range and the caller should
+  // synthesize a GL error.
+  bool SetBoundIndexedTransformFeedbackBuffer(GLuint index, WebGLBuffer*);
+  bool GetBoundIndexedTransformFeedbackBuffer(GLuint index,
+                                              WebGLBuffer** outBuffer) const;
+
+  bool IsBufferBoundToTransformFeedback(WebGLBuffer*);
+
+  void UnbindBuffer(WebGLBuffer*);
+
+  DECLARE_VIRTUAL_TRACE();
+  DECLARE_VIRTUAL_TRACE_WRAPPERS();
 
  protected:
-  explicit WebGLTransformFeedback(WebGL2RenderingContextBase*);
+  explicit WebGLTransformFeedback(WebGL2RenderingContextBase*, TFType);
 
+ private:
+  void DispatchDetached(gpu::gles2::GLES2Interface*);
+  bool HasObject() const override { return object_ != 0; }
   void DeleteObjectImpl(gpu::gles2::GLES2Interface*) override;
 
- private:
-  bool IsTransformFeedback() const override { return true; }
+  GLuint object_;
 
+  TFType type_;
   GLenum target_;
 
+  TraceWrapperMember<WebGLBuffer> bound_transform_feedback_buffer_;
+  HeapVector<TraceWrapperMember<WebGLBuffer>>
+      bound_indexed_transform_feedback_buffers_;
+
   Member<WebGLProgram> program_;
 };
 
 }  // namespace blink
 
 #endif  // WebGLTransformFeedback_h