Japan joins Britain and France against Germany and the Soviet Union

What happens if Japan avoids war in China and offers to join Britain and France against Germany and the Soviet Union in 1939?

Britain and France would likely accept, Allied sea power would become overwhelming, and Italy would have little reason to join Germany.

The scenario removes Japan's war in China and the sanctions that historically pushed relations toward crisis. Japan then offers to join its former First World War allies after Germany and the Soviet Union partition Poland. Britain and France would probably accept because Anglo-Japanese sea power would dominate the global maritime contest even if the continental fighting remained difficult. Mussolini would face a losing proposition and might remain neutral or seek gains against Germany rather than enter on the Axis side. An Italian move into Austria would force Germany to reconsider its attack on France.