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

content/browser/devtools/protocol/devtools_protocol_browsertest.cc

 // Copyright 2013 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 "base/base64.h"
 #include "base/command_line.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
 #include "base/values.h"
 #include "content/public/browser/devtools_agent_host.h"
@@ skipping 452 matching lines @@
   // Ensure that the A.com process is still alive by executing a script in the
   // original tab.
   success = false;
   EXPECT_TRUE(ExecuteScriptAndExtractBool(shell()->web_contents(),
                                           "window.domAutomationController.send("
                                           "    !!window.open('', 'foo'));",
                                           &success));
   EXPECT_TRUE(success);
 }
 
+IN_PROC_BROWSER_TEST_F(DevToolsProtocolTest, ReloadBlankPage) {
+  Shell* window =  Shell::CreateNewWindow(
+      shell()->web_contents()->GetBrowserContext(),
+      GURL("javascript:x=1"),
+      nullptr,
+      gfx::Size());
+  WaitForLoadStop(window->web_contents());
+  Attach();
+  SendCommand("Page.reload", nullptr, false);
+  // Should not crash at this point.
+}
+
 }  // namespace content