Track GL buffer state based on unique resource ID

src/gpu/GrResourceProvider.h

Index: src/gpu/GrResourceProvider.h
diff --git a/src/gpu/GrResourceProvider.h b/src/gpu/GrResourceProvider.h
index fe0b5defa53f245ca27bde3d2efce0d214acdec8..d8e595a47bd5001de88832ace3548f6deb9eeeb8 100644
--- a/src/gpu/GrResourceProvider.h
+++ b/src/gpu/GrResourceProvider.h
@@ -102,7 +102,17 @@ public:
         kNoPendingIO_Flag = kNoPendingIO_ScratchTextureFlag,
     };
 
-    GrBuffer* createBuffer(GrBufferType, size_t size, GrAccessPattern, uint32_t flags);
+    /**
+     * Returns a buffer.
+     *
+     * @param size            minimum size of buffer to return.
+     * @param intendedType    hint to the graphics subsystem about what the buffer will be used for.
+     * @param GrAccessPattern hint to the graphics subsystem about how the data will be accessed.
+     * @param flags           see Flags enum.
+     *
+     * @return the buffer if successful, otherwise nullptr.
+     */
+    GrBuffer* createBuffer(size_t size, GrBufferType intendedType, GrAccessPattern, uint32_t flags);
 
     GrTexture* createApproxTexture(const GrSurfaceDesc& desc, uint32_t flags) {
         SkASSERT(0 == flags || kNoPendingIO_Flag == flags);