MdDialog does not close when browser's back or forward button clicked

[JDillon522]

Bug, feature request, or proposal:

Bug (maybe?)

What is the expected behavior?

When an MdDialog is open and the user clicks the back button the dialog should automatically close.

What is the current behavior?

The dialog stays open.

What are the steps to reproduce?

You can reproduce by launching the documentation example and then clicking back. The dialog stays open. At a minimum, I think it would be a good property set on the MdDialogRef

What is the use-case or motivation for changing an existing behavior?

I can see a use case for keeping it open if you wanted to force user interaction, but I think in general its not a good idea to override UI changes triggered by a browsers back or forward button.

Which versions of Angular, Material, OS, browsers are affected?

angular-cli: 1.0.0-beta.24
node: 6.9.3
os: darwin x64
@angular/common: 2.4.2
@angular/compiler: 2.4.2
@angular/core: 2.4.2
@angular/forms: 2.4.2
@angular/http: 2.4.2
@angular/material: 2.0.0-beta.1
@angular/platform-browser: 2.4.2
@angular/platform-browser-dynamic: 2.4.2
@angular/router: 3.4.2
@angular/compiler-cli: 2.4.2

[jelbourn]

This may be tricky to resolve since we don't want to introduce a dependency on @angular/router in material. It may ultimately end up being something we just have to provide guidance for in the documentation.

[crisbeto]

I think that we could try listening for the pop state event. Will have to check how it plays with stuff like guards.

[jelbourn]

@vicb mentioned he might have an idea on how to do this.