Update mojo sdk to rev 8af2ccff2eee4bfca1043015abee30482a030b30

third_party/mojo/src/mojo/public/go/system/shared_buffer.go

Index: third_party/mojo/src/mojo/public/go/system/shared_buffer.go
diff --git a/third_party/mojo/src/mojo/public/go/system/shared_buffer.go b/third_party/mojo/src/mojo/public/go/system/shared_buffer.go
index a8bdbfa380529b8171a7a18655e6b0f78e067db3..927c7ea3d6433a2ba3a79e2520437822d196fe63 100644
--- a/third_party/mojo/src/mojo/public/go/system/shared_buffer.go
+++ b/third_party/mojo/src/mojo/public/go/system/shared_buffer.go
@@ -31,6 +31,9 @@ type sharedBuffer struct {
 }
 
 func (h *sharedBuffer) DuplicateBufferHandle(opts *DuplicateBufferHandleOptions) (MojoResult, SharedBufferHandle) {
+	h.core.mu.Lock()
+	defer h.core.mu.Unlock()
+
 	cParams := C.MallocDuplicateBufferHandleParams()
 	defer C.FreeDuplicateBufferHandleParams(cParams)
 	result := C.MojoDuplicateBufferHandle(h.mojoHandle.cValue(), opts.cValue(cParams.opts), cParams.duplicate)
@@ -38,6 +41,9 @@ func (h *sharedBuffer) DuplicateBufferHandle(opts *DuplicateBufferHandleOptions)
 }
 
 func (h *sharedBuffer) MapBuffer(offset uint64, numBytes int, flags MojoMapBufferFlags) (MojoResult, []byte) {
+	h.core.mu.Lock()
+	defer h.core.mu.Unlock()
+
 	cParams := C.MallocMapBufferParams()
 	defer C.FreeMapBufferParams(cParams)
 	result := C.MojoMapBuffer(h.mojoHandle.cValue(), C.uint64_t(offset), C.uint64_t(numBytes), cParams.buffer, flags.cValue())
@@ -48,5 +54,8 @@ func (h *sharedBuffer) MapBuffer(offset uint64, numBytes int, flags MojoMapBuffe
 }
 
 func (h *sharedBuffer) UnmapBuffer(buffer []byte) MojoResult {
+	h.core.mu.Lock()
+	defer h.core.mu.Unlock()
+
 	return MojoResult(C.MojoUnmapBuffer(unsafe.Pointer(&buffer[0])))
 }