[identity] Mirror settings in the extension consent flow

This CL enables Mirror for the extension consent flow:
- Makes the account settings dialog appear during the consent flow when
  Gaia passes a Mirror response header. This allows the user to modify
  the list of accounts on their device.
- Keeps the consent flow window opened when it happens. In the case
  the user don't want to modify their accounts, they could go back to
  the consent flow.

Bug: 1026237
Change-Id: I3cdd8bb868e7ec8b80f9cd59f45aee2d06616b1a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2144200Reviewed-by: David Roger <droger@chromium.org>
Commit-Queue: Alex Ilin <alexilin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758789}

chrome/browser/extensions/api/identity/web_auth_flow.cc

@@ -37,6 +37,7 @@
 #include "extensions/browser/extension_system.h"
 #include "extensions/browser/guest_view/web_view/web_view_guest.h"
 #include "net/http/http_response_headers.h"
+#include "net/http/http_status_code.h"
 #include "url/gurl.h"
 #include "url/url_constants.h"
 
@@ -247,6 +248,13 @@ void WebAuthFlow::DidFinishNavigation(
       // the web auth flow.
       DCHECK_EQ(net::ERR_UNKNOWN_URL_SCHEME,
                 navigation_handle->GetNetErrorCode());
+    } else if (navigation_handle->GetResponseHeaders() &&
+               navigation_handle->GetResponseHeaders()->response_code() ==
+                   net::HTTP_NO_CONTENT) {
+      // Navigation to no content URLs is aborted but shouldn't be treated as a
+      // failure.
+      // In particular, Gaia navigates to a no content page to pass Mirror
+      // response headers.
     } else {
       failed = true;
       TRACE_EVENT_NESTABLE_ASYNC_INSTANT1(

chrome/browser/resources/identity_scope_approval_dialog/scope_approval_dialog.js

@@ -43,7 +43,7 @@ function loadAuthUrlAndShowWindow(url, win) {
       windowId = win.id;
     }
     webview.executeScript({file: 'inject.js'});
-  });
+  }, {once: true});
 }
 
 chrome.runtime.onMessageExternal.addListener(function(

chrome/browser/signin/chrome_signin_helper.cc

@@ -29,6 +29,7 @@
 #include "chrome/browser/signin/cookie_reminter_factory.h"
 #include "chrome/browser/signin/dice_response_handler.h"
 #include "chrome/browser/signin/dice_tab_helper.h"
+#include "chrome/browser/signin/header_modification_delegate_impl.h"
 #include "chrome/browser/signin/identity_manager_factory.h"
 #include "chrome/browser/signin/process_dice_header_delegate_impl.h"
 #include "chrome/browser/tab_contents/tab_util.h"
@@ -192,9 +193,19 @@ void ProcessMirrorHeader(
   signin_metrics::LogAccountReconcilorStateOnGaiaResponse(
       account_reconcilor->GetState());
 
+  bool should_ignore_guest_webview = true;
+#if BUILDFLAG(ENABLE_EXTENSIONS)
+  // The mirror headers from some guest web views need to be processed.
+  should_ignore_guest_webview =
+      HeaderModificationDelegateImpl::ShouldIgnoreGuestWebViewRequest(
+          web_contents);
+#endif
+
   // Do not do anything if the navigation happened in the "background".
-  if (!chrome::FindBrowserWithWebContents(web_contents))
+  if (!chrome::FindBrowserWithWebContents(web_contents) &&
+      should_ignore_guest_webview) {
     return;
+  }
 
   // Record the service type.
   UMA_HISTOGRAM_ENUMERATION("AccountManager.ManageAccountsServiceType",