Revert of Consolidate GPU buffer implementations

src/gpu/GrTest.cpp

Index: src/gpu/GrTest.cpp
diff --git a/src/gpu/GrTest.cpp b/src/gpu/GrTest.cpp
index 2b6463d8534835b9ac6d7a1f75a23f294497f3c9..c9b26e284af5bf2d651a42b7d3b056ce71b60404 100644
--- a/src/gpu/GrTest.cpp
+++ b/src/gpu/GrTest.cpp
@@ -345,7 +345,11 @@
         return nullptr;
     }
 
-    GrBuffer* onCreateBuffer(GrBufferType, size_t, GrAccessPattern) override { return nullptr; }
+    GrVertexBuffer* onCreateVertexBuffer(size_t size, bool dynamic) override { return nullptr; }
+
+    GrIndexBuffer* onCreateIndexBuffer(size_t size, bool dynamic) override { return nullptr; }
+
+    GrTransferBuffer* onCreateTransferBuffer(size_t, TransferType) override { return nullptr; }
 
     void onClear(GrRenderTarget*, const SkIRect& rect, GrColor color) override {}
 
@@ -372,7 +376,7 @@
 
     bool onTransferPixels(GrSurface* surface,
                           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;
     }
@@ -406,7 +410,7 @@
 
 void GrContext::initMockContext() {
     GrContextOptions options;
-    options.fBufferMapThreshold = 0;
+    options.fGeometryBufferMapThreshold = 0;
     SkASSERT(nullptr == fGpu);
     fGpu = new MockGpu(this, options);
     SkASSERT(fGpu);