Don't rely on untrusted events in site isolation browser test.

content/browser/site_per_process_browsertest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/site_per_process_browsertest.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 7050 matching lines @@
   FrameTreeNode* child2 = root->child_at(1);
   RenderProcessHost* process1 = child1->current_frame_host()->GetProcess();
   RenderProcessHost* process2 = child2->current_frame_host()->GetProcess();
 
   // Navigate both subframes to a page with a <select> element.
   NavigateFrameToURL(child1, embedded_test_server()->GetURL(
       "b.com", "/site_isolation/page-with-select.html"));
   NavigateFrameToURL(child2, embedded_test_server()->GetURL(
       "c.com", "/site_isolation/page-with-select.html"));
 
+  NativeWebKeyboardEvent event;
+  event.text[0] = ' ';

[Charlie Reis, 2016/06/16 22:35:23]

This isn't entirely clear to me at first glance.  I suppose hitting space when a
select menu is focused opens it?  Maybe you can update the comment below (saying
that and explaining the bit about untrusted events), and then put this event
declaration below the comment?

+  event.timeStampSeconds = 100;
+  event.type = blink::WebKeyboardEvent::Char;
   // Open both <select> menus.  This creates a popup widget in both processes.
   // Wait for and then drop the ViewHostMsg_ShowWidget messages, so that both
   // widgets are left in pending-but-not-shown state.
   scoped_refptr<PendingWidgetMessageFilter> filter1 =
       new PendingWidgetMessageFilter();
   process1->AddFilter(filter1.get());
-  EXPECT_TRUE(ExecuteScript(child1, "openSelectMenu();"));
+  EXPECT_TRUE(ExecuteScript(child1, "focusSelectMenu();"));
+  child1->current_frame_host()->GetRenderWidgetHost()->ForwardKeyboardEvent(
+      event);
   filter1->Wait();
 
   scoped_refptr<PendingWidgetMessageFilter> filter2 =
       new PendingWidgetMessageFilter();
   process2->AddFilter(filter2.get());
-  EXPECT_TRUE(ExecuteScript(child2, "openSelectMenu();"));
+  EXPECT_TRUE(ExecuteScript(child2, "focusSelectMenu();"));
+  child2->current_frame_host()->GetRenderWidgetHost()->ForwardKeyboardEvent(
+      event);
   filter2->Wait();
 
   // At this point, we should have two pending widgets.
   EXPECT_TRUE(
       ContainsKey(web_contents()->pending_widget_views_,
                   std::make_pair(process1->GetID(), filter1->routing_id())));
   EXPECT_TRUE(
       ContainsKey(web_contents()->pending_widget_views_,
                   std::make_pair(process2->GetID(), filter2->routing_id())));
 
@@ skipping 104 matching lines @@
   EXPECT_TRUE(is_fullscreen_allowed(root->child_at(0)));
   EXPECT_TRUE(is_fullscreen_allowed(root->child_at(0)->child_at(0)));
 
   // Cross-site navigation should preserve the fullscreen flags.
   NavigateFrameToURL(root->child_at(0)->child_at(0),
                      embedded_test_server()->GetURL("d.com", "/title1.html"));
   EXPECT_TRUE(is_fullscreen_allowed(root->child_at(0)->child_at(0)));
 }
 
 }  // namespace content