Revert of Consolidate GPU buffer implementations

src/gpu/vk/GrVkCaps.cpp

Index: src/gpu/vk/GrVkCaps.cpp
diff --git a/src/gpu/vk/GrVkCaps.cpp b/src/gpu/vk/GrVkCaps.cpp
index 35aef7a29aef5d931a10efcda1f5008c962712bb..7cfddbab2a4166a948fa8e2b8a8c8706389d1918 100644
--- a/src/gpu/vk/GrVkCaps.cpp
+++ b/src/gpu/vk/GrVkCaps.cpp
@@ -29,7 +29,7 @@
     fUseDrawInsteadOfClear = false; //TODO: figure this out
 
     fMapBufferFlags = kNone_MapFlags; //TODO: figure this out
-    fBufferMapThreshold = SK_MaxS32;  //TODO: figure this out
+    fGeometryBufferMapThreshold = SK_MaxS32;  //TODO: figure this out
 
     fMaxRenderTargetSize = 4096; // minimum required by spec
     fMaxTextureSize = 4096; // minimum required by spec
@@ -112,7 +112,7 @@
 
     // Assuming since we will always map in the end to upload the data we might as well just map
     // from the get go. There is no hard data to suggest this is faster or slower.
-    fBufferMapThreshold = 0;
+    fGeometryBufferMapThreshold = 0;
 
     fMapBufferFlags = kCanMap_MapFlag | kSubset_MapFlag;