Revert of Consolidate GPU buffer implementations

src/gpu/vk/GrVkGpu.h

Index: src/gpu/vk/GrVkGpu.h
diff --git a/src/gpu/vk/GrVkGpu.h b/src/gpu/vk/GrVkGpu.h
index a9a8a41d9757112fe0062dca6cbf02edeb2bb760..a6911f773b57367357c010b34076537f82276c93 100644
--- a/src/gpu/vk/GrVkGpu.h
+++ b/src/gpu/vk/GrVkGpu.h
@@ -136,7 +136,9 @@
     GrRenderTarget* onWrapBackendTextureAsRenderTarget(const GrBackendTextureDesc&,
                                                        GrWrapOwnership) override { return NULL; }
 
-    GrBuffer* onCreateBuffer(GrBufferType, size_t size, GrAccessPattern) override;
+    GrVertexBuffer* onCreateVertexBuffer(size_t size, bool dynamic) override;
+    GrIndexBuffer* onCreateIndexBuffer(size_t size, bool dynamic) override;
+    GrTransferBuffer* onCreateTransferBuffer(size_t size, TransferType type) override;
 
     void onClear(GrRenderTarget*, const SkIRect& rect, GrColor color) override;
 
@@ -159,7 +161,7 @@
 
     bool onTransferPixels(GrSurface*,
                           int left, int top, int width, int height,
-                          GrPixelConfig config, GrBuffer* transferBuffer,
+                          GrPixelConfig config, GrTransferBuffer* buffer,
                           size_t offset, size_t rowBytes) override { return false; }
 
     void onResolveRenderTarget(GrRenderTarget* target) override {}