Instant: Use only one hidden WebContents per profile.

chrome/browser/instant/instant_preloader.cc

Index: chrome/browser/instant/instant_preloader.cc
diff --git a/chrome/browser/instant/instant_preloader.cc b/chrome/browser/instant/instant_preloader.cc
new file mode 100644
index 0000000000000000000000000000000000000000..af96cd9e2d818c5bd34d79a6c557f2f8bea3dca6
--- /dev/null
+++ b/chrome/browser/instant/instant_preloader.cc
@@ -0,0 +1,154 @@
+// 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_preloader.h"
+
+#include "base/stringprintf.h"
+#include "chrome/browser/instant/instant_service.h"
+#include "chrome/browser/instant/search.h"
+#include "chrome/browser/profiles/profile.h"
+#include "content/public/browser/site_instance.h"
+#include "content/public/browser/web_contents.h"
+
+namespace {
+
+const int kStalePageTimeoutMS = 3 * 3600 * 1000;  // 3 hours
+
+// This HTTP header and value are set on loads that originate from Instant.
+const char kInstantHeader[] = "X-Purpose: Instant";
+
+}  // namespace
+
+InstantPreloader::InstantPreloader(InstantService* service)
+    : InstantWebContentsContainer(
+          ALLOW_THIS_IN_INITIALIZER_LIST(this), service),
+      service_(service) {
+  service_->AddObserver(this);
+}
+
+InstantPreloader::~InstantPreloader() {
+  service_->RemoveObserver(this);
+}
+
+void InstantPreloader::InitContents() {
+  if (contents_ && (supports_instant() || contents_->IsLoading()))
+    return;
+
+  GURL instant_url = chrome::search::GetInstantURL(service_->profile());
+  if (!instant_url.is_valid())
+    return;
+
+  content::WebContents::CreateParams create_params(service_->profile(),
+      content::SiteInstance::CreateForURL(service_->profile(), instant_url));
+  contents_.reset(content::WebContents::Create(create_params));
+
+  SetUpContents();
+
+  service_->LogDebugEvent(base::StringPrintf("%p LoadURL '%s'",
+                                             this,
+                                             instant_url.spec().c_str()));
+
+  contents_->GetController().LoadURL(instant_url, content::Referrer(),
+      content::PAGE_TRANSITION_GENERATED, kInstantHeader);
+  contents_->WasHidden();
+
+  stale_page_timer_.Start(FROM_HERE,
+      base::TimeDelta::FromMilliseconds(kStalePageTimeoutMS),
+      this, &InstantPreloader::ReloadContents);
+}
+
+scoped_ptr<content::WebContents> InstantPreloader::ReleaseContents() {
+  TearDownContents();
+  scoped_ptr<content::WebContents> old_contents(contents_.Pass());
+  InitContents();
+  return old_contents.Pass();
+}
+
+void InstantPreloader::RenderViewGone(
+    const content::WebContents* /* contents */) {
+  DeleteContents();
+}
+
+void InstantPreloader::InitSearchBox(
+    const content::WebContents* /* contents */) {
+  page_.DisplayInstantResults(
+      chrome::search::IsInstantPrefEnabled(service_->profile()));
+  page_.ThemeChanged(service_->theme_info());
+  page_.FontChanged(service_->omnibox_font_name(),
+                    service_->omnibox_font_size());
+  page_.MostVisitedItems(service_->most_visited_items());
+}
+
+void InstantPreloader::InstantSupportDetermined(
+    const content::WebContents* /* contents */) {
+  if (!supports_instant())
+    DeleteContents();
+  service_->InstantSupportDetermined();
+}
+
+void InstantPreloader::SetSuggestion(
+    const content::WebContents* /* contents */,
+    const InstantSuggestion& /* suggestion */) {
+}
+
+void InstantPreloader::NavigateToURL(const content::WebContents* /* contents */,
+                                     const GURL& /* url */,
+                                     content::PageTransition /* transition */,
+                                     WindowOpenDisposition /* disposition */) {
+}
+
+void InstantPreloader::ShowOverlay(const content::WebContents* /* contents */,
+                                   int /* height */,
+                                   InstantSizeUnits /* height_units */) {
+}
+
+void InstantPreloader::SetFocusState(const content::WebContents* /* contents */,
+                                     OmniboxFocusState /* focus_state */) {
+}
+
+void InstantPreloader::DeleteMostVisitedItem(
+    const content::WebContents* /* contents */,
+    const GURL& /* url */) {
+}
+
+void InstantPreloader::UndoMostVisitedItemDeletion(
+    const content::WebContents* /* contents */,
+    const GURL& /* url */) {
+}
+
+void InstantPreloader::UndoAllMostVisitedItemDeletions(
+    const content::WebContents* /* contents */) {
+}
+
+void InstantPreloader::InstantStatusChanged() {
+  if (contents_)
+    ReloadContents();
+}
+
+void InstantPreloader::ThemeInfoChanged() {
+  page_.ThemeChanged(service_->theme_info());
+}
+
+void InstantPreloader::MostVisitedItemsChanged() {
+  page_.MostVisitedItems(service_->most_visited_items());
+}
+
+void InstantPreloader::CloseContents(content::WebContents* /* source */) {
+  DeleteContents();
+}
+
+void InstantPreloader::TearDownContents() {
+  InstantWebContentsContainer::TearDownContents();
+  stale_page_timer_.Stop();
+}
+
+void InstantPreloader::DeleteContents() {
+  TearDownContents();
+  contents_.reset();
+}
+
+void InstantPreloader::ReloadContents() {
+  DeleteContents();
+  InitContents();
+}