Bug 1626507 - Remove documentchannel exceptions r=mattwoodrow

This patch removes the excemptions for about:newtab, about:home and
about:blank.

When we switch processes using session restore we sometimes focus the
content area. We mustn't do this if the uri is undefined, this can happen
for some of these pages and we expect the address bar to be focused instead.

Differential Revision: https://phabricator.services.mozilla.com/D80339

browser/components/sessionstore/SessionStore.jsm

@@ -4924,7 +4924,7 @@ var SessionStoreInternal = {
     });
 
     // Focus the tab's content area.
-    if (aTab.selected && !window.isBlankPageURL(uri)) {
+    if (aTab.selected && uri && !window.isBlankPageURL(uri)) {
       browser.focus();
     }
   },

toolkit/modules/E10SUtils.jsm

@@ -134,8 +134,6 @@ const kDocumentChannelDeniedSchemes = ["javascript"];
 const kDocumentChannelDeniedURIs = [
   "about:blank",
   "about:crashcontent",
-  "about:newtab",
-  "about:home",
   "about:printpreview",
 ];