Do not set request's window (#723)

Per whatwg/fetch#1823, this concept is going away. After that change, null-client scenarios will automatically do the right thing, and create no user prompts, which aligns with this spec's desired outcome.

Author: domenic

spec/index.bs

@@ -576,8 +576,6 @@ perform the following steps. This returns an {{USVString}} or failure.
         :: "error"
         :  [=request/client=]
         :: null
-        :  [=request/window=]
-        :: "no-window"
         :  [=request/service-workers mode=]
         :: "none"
         :  [=request/destination=]
@@ -1042,8 +1040,6 @@ or failure.
             :: |rootUrl|
             :  [=request/client=]
             :: null
-            :  [=request/window=]
-            :: "no-window"
             :  [=request/service-workers mode=]
             :: "none"
             :  [=request/destination=]
@@ -1085,8 +1081,6 @@ or failure.
         :: "error"
         :  [=request/client=]
         :: null
-        :  [=request/window=]
-        :: "no-window"
         :  [=request/service-workers mode=]
         :: "none"
         :  [=request/destination=]
@@ -1202,8 +1196,6 @@ returns an {{IdentityProviderAccountList}}.
         :: "error"
         :  [=request/client=]
         :: null
-        :  [=request/window=]
-        :: "no-window"
         :  [=request/service-workers mode=]
         :: "none"
         :  [=request/destination=]
@@ -1285,8 +1277,6 @@ To <dfn>fetch the account picture</dfn> given an {{IdentityProviderAccount}} |ac
         :: |pictureUrl|
         :  [=request/client=]
         :: null
-        :  [=request/window=]
-        :: "no-window"
         :  [=request/service-workers mode=]
         :: "none"
         :  [=request/destination=]
@@ -1351,8 +1341,6 @@ To <dfn>fetch an identity assertion</dfn> given a {{USVString}}
         :: "error"
         :  [=request/client=]
         :: null
-        :  [=request/window=]
-        :: "no-window"
         :  [=request/service-workers mode=]
         :: "none"
         :  [=request/destination=]
@@ -1522,8 +1510,6 @@ an {{IdentityProviderRequestOptions}} |provider|, run the following steps. This
         :: "error"
         :  [=request/client=]
         :: null
-        :  [=request/window=]
-        :: "no-window"
         :  [=request/service-workers mode=]
         :: "none"
         :  [=request/destination=]