Move kChromeSearchScheme out of content since it's a chrome feature.

chrome/browser/instant/instant_service.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 "chrome/browser/instant/instant_service.h"
 
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_types.h"
+#include "content/public/browser/render_process_host.h"
+
 InstantService::InstantService() {
+  registrar_.Add(this,
+                 content::NOTIFICATION_RENDERER_PROCESS_TERMINATED,
+                 content::NotificationService::AllSources());
 }
 
 InstantService::~InstantService() {
 }
 
 void InstantService::AddInstantProcess(int process_id) {
   process_ids_.insert(process_id);
 }
 
-void InstantService::RemoveInstantProcess(int process_id) {
-  process_ids_.erase(process_id);
-}
-
 bool InstantService::IsInstantProcess(int process_id) const {
   return process_ids_.count(process_id) != 0;
 }
 
 int InstantService::GetInstantProcessCount() const {
   return process_ids_.size();
 }
 
 void InstantService::Shutdown() {
   process_ids_.clear();
 }
+
+void InstantService::Observe(int type,
+                             const content::NotificationSource& source,
+                             const content::NotificationDetails& details) {
+  int process_id = content::Source<content::RenderProcessHost>(source)->GetID();
+  process_ids_.erase(process_id);
+}