Make <webview> use out-of-process iframe architecture.

components/guest_view/browser/guest_view_base.cc

Index: components/guest_view/browser/guest_view_base.cc
diff --git a/components/guest_view/browser/guest_view_base.cc b/components/guest_view/browser/guest_view_base.cc
index 0f272a370056268400b9db57b0878386addc6e51..cb2890a9fe7c204fe6958a5c65b93048a4c6d698 100644
--- a/components/guest_view/browser/guest_view_base.cc
+++ b/components/guest_view/browser/guest_view_base.cc
@@ -4,6 +4,7 @@
 
 #include "components/guest_view/browser/guest_view_base.h"
 
+#include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/guest_view/browser/guest_view_event.h"
@@ -18,6 +19,7 @@
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/common/content_switches.h"
 #include "content/public/common/page_zoom.h"
 #include "content/public/common/url_constants.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
@@ -565,6 +567,14 @@ void GuestViewBase::DidNavigateMainFrame(
     const content::FrameNavigateParams& params) {
   if (attached() && ZoomPropagatesFromEmbedderToGuest())
     SetGuestZoomLevelToMatchEmbedder();
+
+  // TODO(lazyboy): This breaks guest visibility in --site-per-process because
+  // we do not take the widget's visibility into account.  We need to also
+  // stay hidden during "visibility:none" state.
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kSitePerProcess)) {
+    web_contents()->WasShown();
+  }
 }
 
 void GuestViewBase::ActivateContents(WebContents* web_contents) {