Add "clear" to about://instant.

chrome/browser/instant/instant_controller.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/browser/instant/instant_controller.h"
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
@@ skipping 828 matching lines @@
 void InstantController::LogDebugEvent(const std::string& info) const {
   DVLOG(1) << info;
 
   debug_events_.push_front(std::make_pair(
       base::Time::Now().ToInternalValue(), info));
   static const size_t kMaxDebugEventSize = 2000;
   if (debug_events_.size() > kMaxDebugEventSize)
     debug_events_.pop_back();
 }
 
+void InstantController::ClearDebugEvents() {
+  debug_events_.clear();
+}
+
 void InstantController::DeleteMostVisitedItem(const GURL& url) {
   history::TopSites* top_sites = browser_->profile()->GetTopSites();
   if (!top_sites)
     return;
 
   top_sites->AddBlacklistedURL(url);
 }
 
 void InstantController::UndoMostVisitedDeletion(const GURL& url) {
   history::TopSites* top_sites = browser_->profile()->GetTopSites();
@@ skipping 656 matching lines @@
     overlay_->SendMostVisitedItems(items);
   if (ntp_)
     ntp_->SendMostVisitedItems(items);
   if (instant_tab_)
     instant_tab_->SendMostVisitedItems(items);
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_INSTANT_SENT_MOST_VISITED_ITEMS,
       content::Source<InstantController>(this),
       content::NotificationService::NoDetails());
 }