Fix a crash when loading a multipart html page.

chrome/browser/extensions/content_script_apitest.cc

Index: chrome/browser/extensions/content_script_apitest.cc
diff --git a/chrome/browser/extensions/content_script_apitest.cc b/chrome/browser/extensions/content_script_apitest.cc
index acd1a75bb725ec20ddb2a3866a15611502d2c0da..a5dda3b86dcc10aefbf6a9a8743b530b1c3325fc 100644
--- a/chrome/browser/extensions/content_script_apitest.cc
+++ b/chrome/browser/extensions/content_script_apitest.cc
@@ -2,13 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/utf_string_conversions.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/browser/extensions/extension_service.h"
-#include "content/browser/tab_contents/tab_contents.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/test/base/ui_test_utils.h"
+#include "content/browser/tab_contents/tab_contents.h"
 #include "googleurl/src/gurl.h"
 #include "net/base/mock_host_resolver.h"
 
@@ -59,6 +60,19 @@ IN_PROC_BROWSER_TEST_F(ExtensionApiTest, ContentScriptIgnoreHostPermissions) {
       "content_scripts/dont_match_host_permissions")) << message_;
 }
 
+IN_PROC_BROWSER_TEST_F(
+    ExtensionApiTest, ContentScriptInjectedIntoMultipartPage) {
+  ASSERT_TRUE(StartTestServer());
+
+  // Start with a renderer already open at a URL.
+  GURL url(test_server()->GetURL("multipart-slow"));
+  ui_test_utils::NavigateToURL(browser(), url);
+
+  string16 title;
+  ui_test_utils::GetCurrentTabTitle(browser(), &title);
+  EXPECT_EQ(std::string("PASS"), UTF16ToUTF8(title));
+}
+
 // crbug.com/39249 -- content scripts js should not run on view source.
 IN_PROC_BROWSER_TEST_F(ExtensionApiTest, ContentScriptViewSource) {
   ASSERT_TRUE(StartTestServer());