Revert of Consolidate GPU buffer implementations

src/gpu/gl/GrGLBuffer.h

-/*
- * Copyright 2016 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef GrGLBuffer_DEFINED
-#define GrGLBuffer_DEFINED
-
-#include "GrBuffer.h"
-#include "gl/GrGLTypes.h"
-
-class GrGLGpu;
-class GrGLCaps;
-
-class GrGLBuffer : public GrBuffer {
-public:
-    static GrGLBuffer* Create(GrGLGpu*, GrBufferType, size_t size, GrAccessPattern);
-
-    ~GrGLBuffer() {
-        // either release or abandon should have been called by the owner of this object.
-        SkASSERT(0 == fBufferID);
-    }
-
-    GrGLenum target() const { return fTarget; }
-    GrGLuint bufferID() const { return fBufferID; }
-    size_t baseOffset() const { return reinterpret_cast<size_t>(fCPUData); }
-
-protected:
-    GrGLBuffer(GrGLGpu*, GrBufferType, size_t size, GrAccessPattern, bool cpuBacked);
-
-    void onAbandon() override;
-    void onRelease() override;
-    void setMemoryBacking(SkTraceMemoryDump* traceMemoryDump,
-                          const SkString& dumpName) const override;
-
-private:
-    GrGLGpu* glGpu() const;
-    const GrGLCaps& glCaps() const;
-
-    void onMap() override;
-    void onUnmap() override;
-    bool onUpdateData(const void* src, size_t srcSizeInBytes) override;
-
-#ifdef SK_DEBUG
-    void validate() const;
-#endif
-
-    void*        fCPUData;
-    GrGLenum     fTarget; // GL_ARRAY_BUFFER or GL_ELEMENT_ARRAY_BUFFER, e.g.
-    GrGLuint     fBufferID;
-    size_t       fSizeInBytes;
-    GrGLenum     fUsage;
-    size_t       fGLSizeInBytes;     // In certain cases we make the size of the GL buffer object
-                                     // smaller or larger than the size in fDesc.
-
-    typedef GrBuffer INHERITED;
-};
-
-#endif