Orwell creates an element of suspense when the smell of chocolate causes Winston to recall a memory "moving vaguely around the edge of his consciousness, a memory of some action which he would have liked to undo but could not."
What possible connection might this have with anything in the past or in the future?
The larger implication of the memory is that it is the one element of consciousness that lies outside of the reach of Big Brother. Winston's memory of something that is "moving vaguely around the edge of his consciousness," is one that exists without the approval or sanction of the external government. This is significant because it proves to a great extent that while Big Brother does control every other aspect of consciousness in Oceania, there are some experiences in the internal, in the subjective realm, that lie outside the control of the government. As this idea is present, the second half of the statement is even more jarring. The idea of possessing "some action which he would have liked to undo, but could not," reflects how Orwell is going to categorize resistance and the attempts of freedom in the setting of Oceania. Winston is seeking to rebel against Oceania, but, such attempts are gong to be futile. The results of both of these visions are that there can be no totality experienced by either the external or the subjective.
This quote is taken from Part Two, Chapter Two, of 1984 when Winston and Julia meet in the woods for the first time. Upon arrival, Julia hands Winston some chocolate. It has a "delightful taste" but also stirs some vague memory in Winston's consciousness.
In terms of a connection, this quote is significant because it foreshadows Winston's memory of the last time he saw his mother, which appears in Part Two, Chapter Seven. Specifically, Winston remembers that the last time he saw his mother was the day on which a chocolate ration was issued. Winston snatched his sister's share of chocolate from her hand and ran out of the house as his mother called out after him. Later, on his return to the house, his mother and sister were gone, and he never saw them again.
This memory is significant because it makes him realize that the Party has eroded the personal loyalties which people like his mother once possessed. In contrast to the people of the past, Party members, for the most part, lack these personal loyalties: through brainwashing and control, they have become loyal only to Big Brother. So, in recalling this memory, Winston realizes that as long as he can maintain his loyalty and commitment to Julia, the Party will never truly control him.