Prevent querying of restricted query values.

chrome/renderer/searchbox/searchbox.cc

 // Copyright 2012 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/renderer/searchbox/searchbox.h"
 
 #include "base/utf_string_conversions.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/renderer/searchbox/searchbox_extension.h"
 #include "content/public/renderer/render_view.h"
@@ skipping 33 matching lines @@
       suggestions[0].behavior == INSTANT_COMPLETE_REPLACE) {
     query_ = suggestions[0].text;
     verbatim_ = true;
     selection_start_ = selection_end_ = query_.size();
   }
   // Explicitly allow empty vector to be sent to the browser.
   render_view()->Send(new ChromeViewHostMsg_SetSuggestions(
       render_view()->GetRoutingID(), render_view()->GetPageId(), suggestions));
 }
 
+void SearchBox::ClearQuery() {
+  query_.clear();
+}
+
 void SearchBox::ShowInstantOverlay(InstantShownReason reason,
                                    int height,
                                    InstantSizeUnits units) {
   render_view()->Send(new ChromeViewHostMsg_ShowInstantOverlay(
       render_view()->GetRoutingID(), render_view()->GetPageId(), reason,
       height, units));
 }
 
 void SearchBox::StartCapturingKeyStrokes() {
   render_view()->Send(new ChromeViewHostMsg_StartCapturingKeyStrokes(
@@ skipping 291 matching lines @@
   GURL url = GURL(ostr.str());
   return UTF8ToUTF16(url.spec());
 }
 
 string16 SearchBox::GenerateFaviconUrl(int id) {
   std::ostringstream ostr;
   ostr << kFaviconUrlPrefix << id;
   GURL url = GURL(ostr.str());
   return UTF8ToUTF16(url.spec());
 }