Add resource provider flag to avoid client-side buffers

src/gpu/GrResourceProvider.h

Index: src/gpu/GrResourceProvider.h
diff --git a/src/gpu/GrResourceProvider.h b/src/gpu/GrResourceProvider.h
index ea3a28adc95f55de8d7a38239a115513e2162f04..68a417a41d89a3eee5a6892b9381a87045873215 100644
--- a/src/gpu/GrResourceProvider.h
+++ b/src/gpu/GrResourceProvider.h
@@ -100,7 +100,12 @@ public:
          *  will occur out of order WRT the operations being flushed.
          *  Make this automatic: https://bug.skia.org/4156
          */
-        kNoPendingIO_Flag = kNoPendingIO_ScratchTextureFlag,
+        kNoPendingIO_Flag = 0x1,
+
+        /** Normally the caps may indicate a preference for client-side buffers. Set this flag when
+         *  creating a buffer to guarantee it resides in GPU memory.
+         */
+        kRequireVBO_Flag = 0x2,

[bsalomon, 2016/07/13 14:34:17]

Can we give this a less GL-centric name? Otherwise lgtm if Jim is OK with the
Vulkan side of things.

[csmartdalton, 2016/07/13 16:39:03]

Done.

     };
 
     /**