Clear VAO dirty bits in NULL back-end.

src/libANGLE/renderer/null/VertexArrayNULL.cpp

@@ -16,4 +16,16 @@ namespace rx
 
 VertexArrayNULL::VertexArrayNULL(const gl::VertexArrayState &data) : VertexArrayImpl(data) {}
 
+angle::Result VertexArrayNULL::syncState(const gl::Context *context,
+                                         const gl::VertexArray::DirtyBits &dirtyBits,
+                                         gl::VertexArray::DirtyAttribBitsArray *attribBits,
+                                         gl::VertexArray::DirtyBindingBitsArray *bindingBits)
+{
+    // Clear the dirty bits in the back-end here.
+    memset(attribBits, 0, sizeof(gl::VertexArray::DirtyAttribBitsArray));
+    memset(bindingBits, 0, sizeof(gl::VertexArray::DirtyBindingBitsArray));
+
+    return angle::Result::Continue;
+}
+
 }  // namespace rx

src/libANGLE/renderer/null/VertexArrayNULL.h

@@ -19,6 +19,11 @@ class VertexArrayNULL : public VertexArrayImpl
 {
   public:
     VertexArrayNULL(const gl::VertexArrayState &data);
+
+    angle::Result syncState(const gl::Context *context,
+                            const gl::VertexArray::DirtyBits &dirtyBits,
+                            gl::VertexArray::DirtyAttribBitsArray *attribBits,
+                            gl::VertexArray::DirtyBindingBitsArray *bindingBits) override;
 };
 
 }  // namespace rx