Fix a crash reported in ChromeFrame on the crash server, which occurs because...

chrome_frame/bho.cc

 // Copyright (c) 2009 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 "chrome_frame/bho.h"
 
 #include <shlguid.h>
 #include <shobjidl.h>
 
 #include "base/file_path.h"
@@ skipping 76 matching lines @@
     bho_current_thread_instance_.Pointer()->Set(NULL);
     Release();
   }
 
   return IObjectWithSiteImpl<Bho>::SetSite(site);
 }
 
 STDMETHODIMP Bho::BeforeNavigate2(IDispatch* dispatch, VARIANT* url,
     VARIANT* flags, VARIANT* target_frame_name, VARIANT* post_data,
     VARIANT* headers, VARIANT_BOOL* cancel) {
+  if (!url || url->vt != VT_BSTR || url->bstrVal == NULL) {
+    DLOG(WARNING) << "Invalid URL passed in";
+    return S_OK;
+  }
+
   ScopedComPtr<IWebBrowser2> web_browser2;
   if (dispatch)
     web_browser2.QueryFrom(dispatch);
 
-  if (!web_browser2 || url->vt != VT_BSTR) {
+  if (!web_browser2) {
     NOTREACHED() << "Can't find WebBrowser2 with given dispatch";
-  } else {
-    DLOG(INFO) << "BeforeNavigate2: " << url->bstrVal;
-    ScopedComPtr<IBrowserService> browser_service;
-    DoQueryService(SID_SShellBrowser, web_browser2, browser_service.Receive());
-    if (!browser_service || !CheckForCFNavigation(browser_service, false)) {
-      referrer_.clear();
-    }
-    url_ = url->bstrVal;
-    ProcessOptInUrls(web_browser2, url->bstrVal);
+    return S_OK;
   }
 
+  DLOG(INFO) << "BeforeNavigate2: " << url->bstrVal;
+  ScopedComPtr<IBrowserService> browser_service;
+  DoQueryService(SID_SShellBrowser, web_browser2, browser_service.Receive());
+  if (!browser_service || !CheckForCFNavigation(browser_service, false)) {
+    referrer_.clear();
+  }
+  url_ = url->bstrVal;
+  ProcessOptInUrls(web_browser2, url->bstrVal);
   return S_OK;
 }
 
 HRESULT Bho::NavigateToCurrentUrlInCF(IBrowserService* browser) {
   DCHECK(browser);
   MarkBrowserOnThreadForCFNavigation(browser);
   ScopedComPtr<IBindCtx> bind_context;
   ScopedComPtr<IMoniker> moniker;
   HRESULT hr = ::CreateBindCtx(0, bind_context.Receive());
   DCHECK(bind_context);
@@ skipping 261 matching lines @@
     ProtocolSinkWrap::UnpatchProtocolHandlers();
   } else if (state_ == PATCH_IBROWSER) {
     vtable_patch::UnpatchInterfaceMethods(IBrowserService_PatchInfo);
   }
 
   HttpNegotiatePatch::Uninitialize();
 
   state_ = UNKNOWN;
 }