Cleanup in InstantTab and InstantController

chrome/browser/ui/search/instant_tab.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/ui/search/instant_tab.h"
 
 #include "chrome/browser/ui/search/search_model.h"
 #include "chrome/browser/ui/search/search_tab_helper.h"
 #include "chrome/common/url_constants.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/web_contents.h"
 
-InstantTab::Delegate::~Delegate() {
-}
+InstantTab::Delegate::~Delegate() {}
+
+InstantTab::InstantTab(Delegate* delegate, content::WebContents* web_contents)
+    : delegate_(delegate), pending_web_contents_(web_contents) {}
 
 InstantTab::~InstantTab() {
   if (web_contents()) {
     SearchTabHelper::FromWebContents(web_contents())->model()->RemoveObserver(
         this);
   }
 }
 
-bool InstantTab::supports_instant() const {
-  return web_contents() &&
-      SearchTabHelper::FromWebContents(web_contents())->SupportsInstant();
-}
-
-bool InstantTab::IsLocal() const {
-  return web_contents() &&
-      web_contents()->GetURL() == GURL(chrome::kChromeSearchLocalNtpUrl);
-}
-
-InstantTab::InstantTab(Delegate* delegate)
-    : delegate_(delegate) {
-}
-
-void InstantTab::Init(content::WebContents* new_web_contents) {
-  ClearContents();
-
-  if (!new_web_contents)
+void InstantTab::Init() {
+  if (!pending_web_contents_)
     return;
 
-  Observe(new_web_contents);
+  Observe(pending_web_contents_);
+  pending_web_contents_ = nullptr;
+
   SearchModel* model =
       SearchTabHelper::FromWebContents(web_contents())->model();
   model->AddObserver(this);
 
   // Already know whether the page supports instant.
   if (model->instant_support() != INSTANT_SUPPORT_UNKNOWN)
     InstantSupportDetermined(model->instant_support() == INSTANT_SUPPORT_YES);
 }
 
 void InstantTab::DidCommitProvisionalLoadForFrame(
     content::RenderFrameHost* render_frame_host,
     const GURL& url,
     ui::PageTransition /* transition_type */) {
-  if (!render_frame_host->GetParent()) {
+  if (!render_frame_host->GetParent())
     delegate_->InstantTabAboutToNavigateMainFrame(web_contents(), url);
-  }
 }
 
 void InstantTab::ModelChanged(const SearchModel::State& old_state,
-                               const SearchModel::State& new_state) {
+                              const SearchModel::State& new_state) {
   if (old_state.instant_support != new_state.instant_support)
     InstantSupportDetermined(new_state.instant_support == INSTANT_SUPPORT_YES);
 }
 
 void InstantTab::InstantSupportDetermined(bool supports_instant) {
   delegate_->InstantSupportDetermined(web_contents(), supports_instant);
 
   // If the page doesn't support Instant, stop listening to it.
-  if (!supports_instant)
-    ClearContents();
+  if (!supports_instant) {
+    if (web_contents()) {
+      SearchTabHelper::FromWebContents(web_contents())->model()->RemoveObserver(
+          this);
+    }
+
+    Observe(nullptr);
+  }
 }
-
-void InstantTab::ClearContents() {
-  if (web_contents()) {
-    SearchTabHelper::FromWebContents(web_contents())->model()->RemoveObserver(
-        this);
-  }
-
-  Observe(NULL);
-}