Update entry page type to include error pages when appropriate.

chrome/browser/ui/zoom/zoom_controller.cc

Index: chrome/browser/ui/zoom/zoom_controller.cc
diff --git a/chrome/browser/ui/zoom/zoom_controller.cc b/chrome/browser/ui/zoom/zoom_controller.cc
index 95ab757f3f7d5bf75cc7c3956e7045ae7fb3afae..45b087588422f4aa7e43ecaff35b2339ffb9538f 100644
--- a/chrome/browser/ui/zoom/zoom_controller.cc
+++ b/chrome/browser/ui/zoom/zoom_controller.cc
@@ -12,6 +12,7 @@
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/common/page_type.h"
 #include "content/public/common/page_zoom.h"
 #include "extensions/common/extension.h"
 #include "grit/theme_resources.h"
@@ -78,10 +79,14 @@ bool ZoomController::SetZoomLevel(double zoom_level) {
 bool ZoomController::SetZoomLevelByExtension(
     double zoom_level,
     const scoped_refptr<const extensions::Extension>& extension) {
+  bool is_error_page =
+      web_contents()->GetController().GetLastCommittedEntry()->GetPageType() ==
+      content::PAGE_TYPE_ERROR;
   // Cannot zoom in disabled mode. Also, don't allow changing zoom level on
-  // a crashed tab.
+  // a crashed tab or an error page.
   if (zoom_mode_ == ZOOM_MODE_DISABLED ||
-      !web_contents()->GetRenderViewHost()->IsRenderViewLive())
+      !web_contents()->GetRenderViewHost()->IsRenderViewLive() ||
+      is_error_page)
     return false;
 
   // Store extension data so that |extension| can be attributed when the zoom