Japanese like pets. There are two types of Japanese, cat type and dog type. Cat type of course has a cat or cats in their home and dog type has dog or dogs. It is very rare to have dog and cat at one place.
There are trends of dogs for Japanese. Until 70s, it was svery popular to have Japanese Spitz, but later the trend to have larger dogs as like Shiba or Akita. Then, the big boom of Siberian Husky comes.
Not like in Europe, having a dog at apartments are not often seen in Japan. Many apartments prohibit the residents to own a pet, especially excluding fish, reptiles, amphibians or small mammals as like hamster. Therefore it is rare to see dog inside the apartment.
Then, taking a dog inside the shops, restaurants or diners are almost impossible. It is quite difficult to find a cafe where you can take your dog with you in Tokyo. The reasons are 1) some people have dog allergy, 2) It is not good for the hygiene.
Actually the restaurant itself does not matter about dog but they have to consider about other customers.