[DevTools] Fix crash in Page.reload when there is no visible entry.

content/browser/devtools/protocol/page_handler.cc

 // Copyright 2014 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/devtools/protocol/page_handler.h"
 
 #include <string>
 
 #include "base/base64.h"
 #include "base/bind.h"
@@ skipping 196 matching lines @@
 }
 
 Response PageHandler::Reload(const bool* ignoreCache,
                              const std::string* script_to_evaluate_on_load,
                              const std::string* script_preprocessor) {
   WebContentsImpl* web_contents = GetWebContents();
   if (!web_contents)
     return Response::InternalError("Could not connect to view");
 
   if (web_contents->IsCrashed() ||
-      web_contents->GetController().GetVisibleEntry()->IsViewSourceMode()) {
+      (web_contents->GetController().GetVisibleEntry() &&
+       web_contents->GetController().GetVisibleEntry()->IsViewSourceMode())) {
     web_contents->GetController().Reload(false);
     return Response::OK();
   } else {
     // Handle reload in renderer except for crashed and view source mode.
     return Response::FallThrough();
   }
 }
 
 Response PageHandler::Navigate(const std::string& url,
                                FrameId* frame_id) {
@@ skipping 283 matching lines @@
 
 void PageHandler::OnColorPicked(int r, int g, int b, int a) {
   scoped_refptr<dom::RGBA> color =
       dom::RGBA::Create()->set_r(r)->set_g(g)->set_b(b)->set_a(a);
   client_->ColorPicked(ColorPickedParams::Create()->set_color(color));
 }
 
 }  // namespace page
 }  // namespace devtools
 }  // namespace content