Upstream rewrite of Instant.

chrome/browser/instant/instant_loader.cc

 // Copyright (c) 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_loader.h"
 
-#include <algorithm>
-#include <string>
-#include <utility>
-#include <vector>
-
-#include "base/command_line.h"
-#include "base/i18n/case_conversion.h"
-#include "base/metrics/histogram.h"
-#include "base/string_number_conversions.h"
-#include "base/timer.h"
-#include "base/utf_string_conversions.h"
-#include "base/values.h"
-#include "chrome/browser/favicon/favicon_service.h"
-#include "chrome/browser/history/history_marshaling.h"
-#include "chrome/browser/history/history_tab_helper.h"
+#include "chrome/browser/content_settings/tab_specific_content_settings.h"
 #include "chrome/browser/instant/instant_loader_delegate.h"
 #include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/search_engines/template_url.h"
 #include "chrome/browser/tab_contents/thumbnail_generator.h"
 #include "chrome/browser/ui/blocked_content/blocked_content_tab_helper.h"
 #include "chrome/browser/ui/constrained_window_tab_helper.h"
 #include "chrome/browser/ui/constrained_window_tab_helper_delegate.h"
 #include "chrome/browser/ui/tab_contents/core_tab_helper.h"
 #include "chrome/browser/ui/tab_contents/core_tab_helper_delegate.h"
 #include "chrome/browser/ui/tab_contents/tab_contents.h"
 #include "chrome/common/chrome_notification_types.h"
-#include "chrome/common/chrome_switches.h"
 #include "chrome/common/render_messages.h"
-#include "content/public/browser/favicon_status.h"
 #include "content/public/browser/navigation_controller.h"
-#include "content/public/browser/navigation_details.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/notification_details.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/render_view_host.h"
-#include "content/public/browser/render_widget_host.h"
 #include "content/public/browser/render_widget_host_view.h"
-#include "content/public/browser/session_storage_namespace.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_delegate.h"
-#include "content/public/browser/web_contents_view.h"
-#include "net/http/http_util.h"
-#include "ui/base/l10n/l10n_util.h"
-#include "ui/gfx/codec/png_codec.h"
-
-using content::NavigationController;
-using content::NavigationEntry;
-using content::RenderViewHost;
-using content::RenderWidgetHost;
-using content::SessionStorageNamespace;
-using content::WebContents;
-
-namespace {
-
-// Number of ms to delay before updating the omnibox bounds. This is only used
-// when the bounds of the omnibox shrinks. If the bounds grows, we update
-// immediately.
-const int kUpdateBoundsDelayMS = 1000;

[sky, 2012/07/17 18:21:42]

I guess we're removing this because it doesn't makes sense with the new
behavior, right? But remember that we need to support both for at least some
amount of time. So, I don't think we can remove this.

[sreeram, 2012/07/18 01:29:45]

It's not being removed. It's just being moved to instant_controller.cc (line
56), which centralizes the logic for when to update the bounds.

[sreeram, 2012/07/18 01:29:45]

It's not being removed. It's just being moved to instant_controller.cc (line
56).

[Jered, 2012/07/18 17:38:58]

This still exists, but is now in the controller.

-
-// If this status code is seen instant is disabled for the specified host.
-const int kHostBlacklistStatusCode = 403;

[sky, 2012/07/17 18:21:42]

Why are you removing this? We've documented allowing this for the API and folks
on the search side wanted this as a way to disable instant if necessary.

[sreeram, 2012/07/18 01:29:45]

I don't see it being documented at http://dev.chromium.org/searchbox. The search
folks already have and use another mechanism for disabling Instant, which is to
simply not define window.chrome.sv (v1 API) or window.chrome.searchbox.onsubmit
(v2 API). It has exactly the same effect as returning 403 with respect to not
using and blacklisting the search provider for Instant. None of these are also
documented, by the way.

-
-enum PreviewUsageType {
-  PREVIEW_CREATED,
-  PREVIEW_DELETED,
-  PREVIEW_LOADED,
-  PREVIEW_SHOWN,
-  PREVIEW_COMMITTED,
-  PREVIEW_NUM_TYPES,
-};
-
-void AddPreviewUsageForHistogram(TemplateURLID template_url_id,
-                                 PreviewUsageType usage,
-                                 const std::string& group) {
-  DCHECK(0 <= usage && usage < PREVIEW_NUM_TYPES);
-  // Only track the histogram for the instant loaders, for now.
-  if (template_url_id) {
-    base::Histogram* histogram = base::LinearHistogram::FactoryGet(
-        "Instant.Previews" + group, 1, PREVIEW_NUM_TYPES, PREVIEW_NUM_TYPES + 1,
-        base::Histogram::kUmaTargetedHistogramFlag);
-    histogram->Add(usage);
-  }
-}
-
-SessionStorageNamespace* GetSessionStorageNamespace(TabContents* tab) {
-  return tab->web_contents()->GetController().GetSessionStorageNamespace();
-}
-
-}  // namespace
-
-// static
-const char* const InstantLoader::kInstantHeader = "X-Purpose";
-// static
-const char* const InstantLoader::kInstantHeaderValue = "instant";

[sky, 2012/07/17 18:21:42]

Similar comments for the header and header-value. These are the in spec and
while Google may not want them, they should be there.

[dominich, 2012/07/17 18:42:19]

They are - see 262.

They were removed as constants but they're still being sent.

[Jered, 2012/07/18 17:38:58]

I have re-added these below. I chose not to expose them because they're an
implementation detail of the loader.

-
-// FrameLoadObserver is responsible for determining if the page supports
-// instant after it has loaded.
-class InstantLoader::FrameLoadObserver : public content::NotificationObserver {
- public:
-  FrameLoadObserver(InstantLoader* loader,
-                    WebContents* web_contents,
-                    const string16& text,
-                    bool verbatim)
-      : loader_(loader),
-        web_contents_(web_contents),
-        text_(text),
-        verbatim_(verbatim),
-        unique_id_(
-            web_contents_->GetController().GetPendingEntry()->GetUniqueID()) {
-    registrar_.Add(this, content::NOTIFICATION_LOAD_COMPLETED_MAIN_FRAME,
-                   content::Source<WebContents>(web_contents_));
-  }
-
-  // Sets the text to send to the page.
-  void set_text(const string16& text) { text_ = text; }
-
-  // Sets whether verbatim results are obtained rather than predictive.
-  void set_verbatim(bool verbatim) { verbatim_ = verbatim; }
-
-  // content::NotificationObserver:
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
-
- private:
-  InstantLoader* loader_;
-
-  // The WebContents we're listening for changes on.
-  WebContents* web_contents_;
-
-  // Text to send down to the page.
-  string16 text_;
-
-  // Whether verbatim results are obtained.
-  bool verbatim_;
-
-  // unique_id of the NavigationEntry we're waiting on.
-  const int unique_id_;
-
-  // Registers and unregisters us for notifications.
-  content::NotificationRegistrar registrar_;
-
-  DISALLOW_COPY_AND_ASSIGN(FrameLoadObserver);
-};
-
-void InstantLoader::FrameLoadObserver::Observe(
-    int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
-  switch (type) {
-    case content::NOTIFICATION_LOAD_COMPLETED_MAIN_FRAME: {
-      int page_id = *(content::Details<int>(details).ptr());
-      NavigationEntry* active_entry =
-          web_contents_->GetController().GetActiveEntry();
-      if (!active_entry || active_entry->GetPageID() != page_id ||
-          active_entry->GetUniqueID() != unique_id_) {
-        return;
-      }
-      loader_->SendBoundsToPage(true);
-      // TODO: support real cursor position.
-      int text_length = static_cast<int>(text_.size());
-      RenderViewHost* host = web_contents_->GetRenderViewHost();
-      host->Send(new ChromeViewMsg_DetermineIfPageSupportsInstant(
-          host->GetRoutingID(), text_, verbatim_, text_length, text_length));
-      break;
-    }
-    default:
-      NOTREACHED();
-      break;
-  }
-}
+#include "content/public/browser/web_contents_observer.h"
 
 // WebContentsDelegateImpl -----------------------------------------------------
 
 class InstantLoader::WebContentsDelegateImpl
-    : public content::WebContentsDelegate,
+    : public ConstrainedWindowTabHelperDelegate,
       public CoreTabHelperDelegate,
-      public ConstrainedWindowTabHelperDelegate,
-      public content::NotificationObserver,
+      public content::WebContentsDelegate,
       public content::WebContentsObserver {
  public:
   explicit WebContentsDelegateImpl(InstantLoader* loader);
 
-  // Invoked prior to loading a new URL.
-  void PrepareForNewLoad();
-
-  // Invoked when the preview paints. Invokes PreviewPainted on the loader.
-  void PreviewPainted();
-
   bool is_mouse_down_from_activate() const {
     return is_mouse_down_from_activate_;
   }
 
-  void set_user_typed_before_load() { user_typed_before_load_ = true; }
+  // ConstrainedWindowTabHelperDelegate:
+  virtual bool ShouldFocusConstrainedWindow() OVERRIDE;
 
-  // Sets the last URL that will be added to history when CommitHistory is
-  // invoked and removes all but the first navigation.
-  void SetLastHistoryURLAndPrune(const GURL& url);
-
-  // Commits the currently buffered history.
-  void CommitHistory(bool supports_instant);
-
-  void RegisterForPaintNotifications(RenderWidgetHost* render_widget_host);
-
-  void UnregisterForPaintNotifications();
-
-  // NotificationObserver:
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
+  // CoreTabHelperDelegate:
+  virtual void SwapTabContents(TabContents* old_tc,
+                               TabContents* new_tc) OVERRIDE;
 
   // content::WebContentsDelegate:
-  virtual void NavigationStateChanged(const WebContents* source,
-                                      unsigned changed_flags) OVERRIDE;
-  virtual void AddNavigationHeaders(const GURL& url,
-                                    std::string* headers) OVERRIDE;
   virtual bool ShouldSuppressDialogs() OVERRIDE;
-  virtual void BeforeUnloadFired(content::WebContents* tab,
-                                 bool proceed,
-                                 bool* proceed_to_fire_unload) OVERRIDE;
-  virtual void SetFocusToLocationBar(bool select_all) OVERRIDE;
   virtual bool ShouldFocusPageAfterCrash() OVERRIDE;
-  virtual void WebContentsFocused(WebContents* contents) OVERRIDE;
   virtual void LostCapture() OVERRIDE;
-  // If the user drags, we won't get a mouse up (at least on Linux). Commit the
-  // instant result when the drag ends, so that during the drag the page won't
-  // move around.
-  virtual void DragEnded() OVERRIDE;
+  virtual void WebContentsFocused(content::WebContents* contents) OVERRIDE;
   virtual bool CanDownload(content::RenderViewHost* render_view_host,
                            int request_id,
                            const std::string& request_method) OVERRIDE;
   virtual void HandleMouseUp() OVERRIDE;
   virtual void HandleMouseActivate() OVERRIDE;
+  virtual void DragEnded() OVERRIDE;
   virtual bool OnGoToEntryOffset(int offset) OVERRIDE;
   virtual bool ShouldAddNavigationToHistory(
       const history::HistoryAddPageArgs& add_page_args,
       content::NavigationType navigation_type) OVERRIDE;
 
-  // CoreTabHelperDelegate:
-  virtual void SwapTabContents(TabContents* old_tc,
-                               TabContents* new_tc) OVERRIDE;
-
-  // ConstrainedWindowTabHelperDelegate:
-  virtual void WillShowConstrainedWindow(TabContents* source) OVERRIDE;
-  virtual bool ShouldFocusConstrainedWindow() OVERRIDE;
-
   // content::WebContentsObserver:
+  virtual void DidFinishLoad(int64 frame_id,
+                             const GURL& validated_url,
+                             bool is_main_frame) OVERRIDE;
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
-  virtual void DidFailProvisionalLoad(
-      int64 frame_id,
-      bool is_main_frame,
-      const GURL& validated_url,
-      int error_code,
-      const string16& error_description,
-      content::RenderViewHost* render_view_host) OVERRIDE;
 
  private:
-  typedef std::vector<scoped_refptr<history::HistoryAddPageArgs> >
-      AddPageVector;
-
   // Message from renderer indicating the page has suggestions.
   void OnSetSuggestions(
-      int32 page_id,
+      int page_id,
       const std::vector<std::string>& suggestions,
       InstantCompleteBehavior behavior);
 
-  // Messages from the renderer when we've determined whether the page supports
-  // instant.
-  void OnInstantSupportDetermined(int32 page_id, bool result);
+  // Message from the renderer determining whether it supports the Instant API.
+  void OnInstantSupportDetermined(int page_id, bool result);
 
   void CommitFromMouseReleaseIfNecessary();
+  void MaybeSetAndNotifyInstantSupportDetermined(bool supports_instant);
 
   InstantLoader* loader_;
 
-  content::NotificationRegistrar registrar_;
-
-  // If we are registered for paint notifications on a RenderWidgetHost this
-  // will contain a pointer to it.
-  RenderWidgetHost* registered_render_widget_host_;
-
-  // Used to cache data that needs to be added to history. Normally entries are
-  // added to history as the user types, but for instant we only want to add the
-  // items to history if the user commits instant. So, we cache them here and if
-  // committed then add the items to history.
-  AddPageVector add_page_vector_;
-
-  // Are we we waiting for a NavigationType of NEW_PAGE? If we're waiting for
-  // NEW_PAGE navigation we don't add history items to add_page_vector_.
-  bool waiting_for_new_page_;
-
   // True if the mouse is down from an activate.
   bool is_mouse_down_from_activate_;
 
-  // True if the user typed in the search box before the page loaded.
-  bool user_typed_before_load_;
-
   DISALLOW_COPY_AND_ASSIGN(WebContentsDelegateImpl);
 };
 
 InstantLoader::WebContentsDelegateImpl::WebContentsDelegateImpl(
     InstantLoader* loader)
-    : content::WebContentsObserver(loader->preview_contents()->web_contents()),
+    : content::WebContentsObserver(loader->preview_contents_->web_contents()),
       loader_(loader),
-      registered_render_widget_host_(NULL),
-      waiting_for_new_page_(true),
-      is_mouse_down_from_activate_(false),
-      user_typed_before_load_(false) {
-  DCHECK(loader->preview_contents());
-  registrar_.Add(this, content::NOTIFICATION_INTERSTITIAL_ATTACHED,
-      content::Source<WebContents>(loader->preview_contents()->web_contents()));
+      is_mouse_down_from_activate_(false) {
 }
 
-void InstantLoader::WebContentsDelegateImpl::PrepareForNewLoad() {
-  user_typed_before_load_ = false;
-  waiting_for_new_page_ = true;
-  add_page_vector_.clear();
-  UnregisterForPaintNotifications();
+bool InstantLoader::WebContentsDelegateImpl::ShouldFocusConstrainedWindow() {
+  // Return false so that constrained windows are not initially focused. If we
+  // did otherwise the preview would prematurely get committed when focus goes
+  // to the constrained window.
+  return false;
 }
 
-void InstantLoader::WebContentsDelegateImpl::PreviewPainted() {
-  loader_->PreviewPainted();
-}
-
-void InstantLoader::WebContentsDelegateImpl::SetLastHistoryURLAndPrune(
-    const GURL& url) {
-  if (add_page_vector_.empty())
-    return;
-
-  history::HistoryAddPageArgs* args = add_page_vector_.front().get();
-  args->url = url;
-  args->redirects.clear();
-  args->redirects.push_back(url);
-
-  // Prune all but the first entry.
-  add_page_vector_.erase(add_page_vector_.begin() + 1,
-                         add_page_vector_.end());
-}
-
-void InstantLoader::WebContentsDelegateImpl::CommitHistory(
-    bool supports_instant) {
-  TabContents* tab = loader_->preview_contents();
-  if (tab->profile()->IsOffTheRecord())
-    return;
-
-  for (size_t i = 0; i < add_page_vector_.size(); ++i) {
-    tab->history_tab_helper()->UpdateHistoryForNavigation(
-      add_page_vector_[i].get());
-  }
-
-  NavigationEntry* active_entry =
-      tab->web_contents()->GetController().GetActiveEntry();
-  if (!active_entry) {
-    // It appears to be possible to get here with no active entry. This seems
-    // to be possible with an auth dialog, but I can't narrow down the
-    // circumstances. If you hit this, file a bug with the steps you did and
-    // assign it to me (sky).
-    NOTREACHED();
-    return;
-  }
-  tab->history_tab_helper()->UpdateHistoryPageTitle(*active_entry);
-
-  FaviconService* favicon_service =
-      tab->profile()->GetFaviconService(Profile::EXPLICIT_ACCESS);
-
-  if (favicon_service && active_entry->GetFavicon().valid &&
-      !active_entry->GetFavicon().bitmap.empty()) {
-    std::vector<unsigned char> image_data;
-    gfx::PNGCodec::EncodeBGRASkBitmap(active_entry->GetFavicon().bitmap, false,
-                                      &image_data);
-    favicon_service->SetFavicon(active_entry->GetURL(),
-                                active_entry->GetFavicon().url,
-                                image_data,
-                                history::FAVICON);
-    if (supports_instant && !add_page_vector_.empty()) {
-      // If we're using the instant API, then we've tweaked the url that is
-      // going to be added to history. We need to also set the favicon for the
-      // url we're adding to history (see comment in ReleasePreviewContents
-      // for details).
-      favicon_service->SetFavicon(add_page_vector_.back()->url,
-                                  active_entry->GetFavicon().url,
-                                  image_data,
-                                  history::FAVICON);
-    }
-  }
-}
-
-void InstantLoader::WebContentsDelegateImpl::RegisterForPaintNotifications(
-    RenderWidgetHost* render_widget_host) {
-  DCHECK(registered_render_widget_host_ == NULL);
-  registered_render_widget_host_ = render_widget_host;
-  content::Source<RenderWidgetHost> source =
-      content::Source<RenderWidgetHost>(registered_render_widget_host_);
-  registrar_.Add(
-      this,
-      content::NOTIFICATION_RENDER_WIDGET_HOST_DID_UPDATE_BACKING_STORE,
-      source);
-  registrar_.Add(this, content::NOTIFICATION_RENDER_WIDGET_HOST_DESTROYED,
-                 source);
-}
-
-void InstantLoader::WebContentsDelegateImpl::UnregisterForPaintNotifications() {
-  if (registered_render_widget_host_) {
-    content::Source<RenderWidgetHost> source =
-        content::Source<RenderWidgetHost>(registered_render_widget_host_);
-    registrar_.Remove(
-        this,
-        content::NOTIFICATION_RENDER_WIDGET_HOST_DID_UPDATE_BACKING_STORE,
-        source);
-    registrar_.Remove(this, content::NOTIFICATION_RENDER_WIDGET_HOST_DESTROYED,
-                      source);
-    registered_render_widget_host_ = NULL;
-  }
-}
-
-void InstantLoader::WebContentsDelegateImpl::Observe(
-    int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
-  switch (type) {
-    case content::NOTIFICATION_RENDER_WIDGET_HOST_DID_UPDATE_BACKING_STORE:
-      UnregisterForPaintNotifications();
-      PreviewPainted();
-      break;
-    case content::NOTIFICATION_RENDER_WIDGET_HOST_DESTROYED:
-      UnregisterForPaintNotifications();
-      break;
-    case content::NOTIFICATION_INTERSTITIAL_ATTACHED:
-      PreviewPainted();
-      break;
-    default:
-      NOTREACHED() << "Got a notification we didn't register for.";
-  }
-}
-
-void InstantLoader::WebContentsDelegateImpl::NavigationStateChanged(
-    const WebContents* source,
-    unsigned changed_flags) {
-  if (!loader_->ready() && !registered_render_widget_host_ &&
-      source->GetController().GetEntryCount()) {
-    // The load has been committed. Install an observer that waits for the
-    // first paint then makes the preview active. We wait for the load to be
-    // committed before waiting on paint as there is always an initial paint
-    // when a new renderer is created from the resize so that if we showed the
-    // preview after the first paint we would end up with a white rect.
-    content::RenderWidgetHostView *rwhv = source->GetRenderWidgetHostView();
-    if (rwhv)
-      RegisterForPaintNotifications(rwhv->GetRenderWidgetHost());
-  } else if (source->IsCrashed()) {
-    PreviewPainted();
-  }
-}
-
-void InstantLoader::WebContentsDelegateImpl::AddNavigationHeaders(
-    const GURL& url,
-    std::string* headers) {
-  net::HttpUtil::AppendHeaderIfMissing(kInstantHeader, kInstantHeaderValue,
-                                       headers);
+void InstantLoader::WebContentsDelegateImpl::SwapTabContents(
+    TabContents* old_tc,
+    TabContents* new_tc) {
+  // If this is being called, something is swapping in to our preview_contents_
+  // before we've added it to the tab strip.
+  loader_->ReplacePreviewContents(old_tc, new_tc);
 }
 
 bool InstantLoader::WebContentsDelegateImpl::ShouldSuppressDialogs() {
-  // Any message shown during instant cancels instant, so we suppress them.
+  // Any message shown during Instant cancels Instant, so we suppress them.
   return true;
 }
 
-void InstantLoader::WebContentsDelegateImpl::BeforeUnloadFired(
-    WebContents* tab,
-    bool proceed,
-    bool* proceed_to_fire_unload) {
-}
-
-void InstantLoader::WebContentsDelegateImpl::SetFocusToLocationBar(
-    bool select_all) {
-}
-
 bool InstantLoader::WebContentsDelegateImpl::ShouldFocusPageAfterCrash() {
   return false;
 }
 
-void InstantLoader::WebContentsDelegateImpl::WebContentsFocused(
-    WebContents* contents) {
-  loader_->delegate_->InstantLoaderContentsFocused();
-}
-
 void InstantLoader::WebContentsDelegateImpl::LostCapture() {
   CommitFromMouseReleaseIfNecessary();
 }
 
-void InstantLoader::WebContentsDelegateImpl::DragEnded() {
-  CommitFromMouseReleaseIfNecessary();
+void InstantLoader::WebContentsDelegateImpl::WebContentsFocused(
+    content::WebContents* contents) {
+  loader_->loader_delegate_->InstantLoaderContentsFocused(loader_);
 }
 
 bool InstantLoader::WebContentsDelegateImpl::CanDownload(
-        RenderViewHost* render_view_host,
-        int request_id,
-        const std::string& request_method) {
+    content::RenderViewHost* render_view_host,
+    int request_id,
+    const std::string& request_method) {
   // Downloads are disabled.
   return false;
 }
 
 void InstantLoader::WebContentsDelegateImpl::HandleMouseUp() {
   CommitFromMouseReleaseIfNecessary();
 }
 
 void InstantLoader::WebContentsDelegateImpl::HandleMouseActivate() {
   is_mouse_down_from_activate_ = true;
 }
 
+void InstantLoader::WebContentsDelegateImpl::DragEnded() {
+  // If the user drags, we won't get a mouse up (at least on Linux). Commit the
+  // Instant result when the drag ends, so that during the drag the page won't
+  // move around.
+  CommitFromMouseReleaseIfNecessary();
+}
+
 bool InstantLoader::WebContentsDelegateImpl::OnGoToEntryOffset(int offset) {
   return false;
 }
 
 bool InstantLoader::WebContentsDelegateImpl::ShouldAddNavigationToHistory(
     const history::HistoryAddPageArgs& add_page_args,
     content::NavigationType navigation_type) {
-  if (waiting_for_new_page_ &&
-      navigation_type == content::NAVIGATION_TYPE_NEW_PAGE) {
-    waiting_for_new_page_ = false;
-  }
-
-  if (!waiting_for_new_page_) {
-    add_page_vector_.push_back(
-        scoped_refptr<history::HistoryAddPageArgs>(add_page_args.Clone()));
-  }
   return false;
 }
 
-// If this is being called, something is swapping in to our preview_contents_
-// before we've added it to the tab strip.
-void InstantLoader::WebContentsDelegateImpl::SwapTabContents(
-    TabContents* old_tc,
-    TabContents* new_tc) {
-  loader_->ReplacePreviewContents(old_tc, new_tc);
-}
-
-bool InstantLoader::WebContentsDelegateImpl::ShouldFocusConstrainedWindow() {
-  // Return false so that constrained windows are not initially focused. If
-  // we did otherwise the preview would prematurely get committed when focus
-  // goes to the constrained window.
-  return false;
-}
-
-void InstantLoader::WebContentsDelegateImpl::WillShowConstrainedWindow(
-    TabContents* source) {
-  if (!loader_->ready()) {
-    // A constrained window shown for an auth may not paint. Show the preview
-    // contents.
-    UnregisterForPaintNotifications();
-    loader_->ShowPreview();
+void InstantLoader::WebContentsDelegateImpl::DidFinishLoad(
+    int64 frame_id,
+    const GURL& validated_url,
+    bool is_main_frame) {
+  if (is_main_frame && !loader_->supports_instant_) {
+    Send(new ChromeViewMsg_DetermineIfPageSupportsInstant(routing_id()));
+    loader_->loader_delegate_->InstantLoaderPreviewLoaded(loader_);
   }
 }
 
 bool InstantLoader::WebContentsDelegateImpl::OnMessageReceived(
     const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(WebContentsDelegateImpl, message)
     IPC_MESSAGE_HANDLER(ChromeViewHostMsg_SetSuggestions, OnSetSuggestions)
     IPC_MESSAGE_HANDLER(ChromeViewHostMsg_InstantSupportDetermined,
                         OnInstantSupportDetermined)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
-void InstantLoader::WebContentsDelegateImpl::DidFailProvisionalLoad(
-    int64 frame_id,
-    bool is_main_frame,
-    const GURL& validated_url,
-    int error_code,
-    const string16& error_description,
-    content::RenderViewHost* render_view_host) {
-  if (validated_url == loader_->url_) {
-    // This typically happens with downloads (which are disabled with
-    // instant active). To ensure the download happens when the user presses
-    // enter we set needs_reload_ to true, which triggers a reload.
-    loader_->needs_reload_ = true;
-  }
-}
-
 void InstantLoader::WebContentsDelegateImpl::OnSetSuggestions(
     int32 page_id,
     const std::vector<std::string>& suggestions,
     InstantCompleteBehavior behavior) {
-  TabContents* source = loader_->preview_contents();
-  NavigationEntry* entry =
-      source->web_contents()->GetController().GetActiveEntry();
-  if (!entry || page_id != entry->GetPageID())
-    return;
-
-  if (suggestions.empty())
-    loader_->SetCompleteSuggestedText(string16(), behavior);
-  else
-    loader_->SetCompleteSuggestedText(UTF8ToUTF16(suggestions[0]), behavior);
+  content::NavigationEntry* entry = loader_->preview_contents_->web_contents()->
+                                        GetController().GetActiveEntry();
+  if (entry && page_id == entry->GetPageID()) {
+    MaybeSetAndNotifyInstantSupportDetermined(true);
+    loader_->loader_delegate_->SetSuggestions(loader_, suggestions, behavior);
+  }
 }
 
 void InstantLoader::WebContentsDelegateImpl::OnInstantSupportDetermined(
-    int32 page_id,
+    int page_id,
     bool result) {
-  WebContents* source = loader_->preview_contents()->web_contents();
-  if (!source->GetController().GetActiveEntry() ||
-      page_id != source->GetController().GetActiveEntry()->GetPageID())
+  content::NavigationEntry* entry = loader_->preview_contents_->web_contents()->
+                                        GetController().GetActiveEntry();
+  if (entry && page_id == entry->GetPageID())
+    MaybeSetAndNotifyInstantSupportDetermined(result);
+}
+
+
+void InstantLoader::WebContentsDelegateImpl
+    ::CommitFromMouseReleaseIfNecessary() {
+  if (is_mouse_down_from_activate_) {
+    is_mouse_down_from_activate_ = false;
+    loader_->loader_delegate_->CommitInstantLoader(loader_);
+  }
+}
+
+void InstantLoader::WebContentsDelegateImpl
+    ::MaybeSetAndNotifyInstantSupportDetermined(bool supports_instant) {
+  // If we already determined that the loader supports Instant, nothing to do.
+  if (loader_->supports_instant_)
     return;
 
-  content::Details<const bool> details(&result);
+  loader_->supports_instant_ = supports_instant;
+  loader_->loader_delegate_->InstantSupportDetermined(loader_,
+                                                      supports_instant);
+  content::Details<const bool> details(&supports_instant);
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_INSTANT_SUPPORT_DETERMINED,
       content::NotificationService::AllSources(),
       details);
 
-  if (result)
-    loader_->PageFinishedLoading();
-  else
-    loader_->PageDoesntSupportInstant(user_typed_before_load_);
-}
-
-void InstantLoader::WebContentsDelegateImpl
-    ::CommitFromMouseReleaseIfNecessary() {
-  bool was_down = is_mouse_down_from_activate_;
-  is_mouse_down_from_activate_ = false;
-  if (was_down && loader_->ShouldCommitInstantOnMouseUp())
-    loader_->CommitInstantLoader();
+  // If the page doesn't support the Instant API, InstantController schedules
+  // the loader for destruction. Stop sending the controller any more messages,
+  // by severing the connection from the WebContents to us (its delegate).
+  if (!supports_instant)
+    loader_->preview_contents_->web_contents()->SetDelegate(NULL);
 }
 
 // InstantLoader ---------------------------------------------------------------
 
 InstantLoader::InstantLoader(InstantLoaderDelegate* delegate,
-                             TemplateURLID id,
-                             const std::string& group)
-    : delegate_(delegate),
-      template_url_id_(id),
-      ready_(false),
-      http_status_ok_(true),
-      last_transition_type_(content::PAGE_TRANSITION_LINK),
-      verbatim_(false),
-      needs_reload_(false),
-      group_(group) {
+                             const string16& loader_id,
+                             const GURL& instant_url,
+                             const TabContents* tab_contents)
+    : loader_delegate_(delegate),
+      loader_id_(loader_id),
+      preview_contents_(new TabContents(content::WebContents::Create(
+          tab_contents->profile(), NULL, MSG_ROUTING_NONE,
+          tab_contents->web_contents(),
+          tab_contents->web_contents()->GetController().
+                                        GetSessionStorageNamespace()))),
+      preview_delegate_(new WebContentsDelegateImpl(
+          ALLOW_THIS_IN_INITIALIZER_LIST(this))),
+      supports_instant_(false),
+      instant_url_(instant_url) {
+  SetupPreviewContents();
+  preview_contents_->web_contents()->GetController().LoadURL(instant_url,
+      content::Referrer(), content::PAGE_TRANSITION_GENERATED,
+      "X-Purpose: Instant");
+  preview_contents_->web_contents()->WasHidden();
 }
 
 InstantLoader::~InstantLoader() {
-  registrar_.RemoveAll();
-
-  // Delete the TabContents before the delegate as the TabContents
-  // holds a reference to the delegate.
   if (preview_contents())
-    AddPreviewUsageForHistogram(template_url_id_, PREVIEW_DELETED, group_);
-  preview_contents_.reset();
+    preview_contents_->web_contents()->SetDelegate(NULL);
 }
 
-bool InstantLoader::Update(TabContents* tab_contents,
-                           const TemplateURL* template_url,
-                           const GURL& url,
-                           content::PageTransition transition_type,
-                           const string16& user_text,
-                           bool verbatim,
-                           string16* suggested_text) {
-  DCHECK(!url.is_empty() && url.is_valid());
-
-  // Strip leading ?.
-  string16 new_user_text =
-      !user_text.empty() && (UTF16ToWide(user_text)[0] == L'?') ?
-      user_text.substr(1) : user_text;
-
-  // We should preserve the transition type regardless of whether we're already
-  // showing the url.
-  last_transition_type_ = transition_type;
-
-  // If state hasn't changed, reuse the last suggestion. There are two cases:
-  // 1. If no template url (not using instant API), then we only care if the url
-  //    changes.
-  // 2. Template url (using instant API) then the important part is if the
-  //    user_text changes.
-  //    We have to be careful in checking user_text as in some situations
-  //    InstantController passes in an empty string (when it knows the user_text
-  //    won't matter).
-  if ((!template_url_id_ && url_ == url) ||
-      (template_url_id_ &&
-       (new_user_text.empty() || user_text_ == new_user_text))) {
-    suggested_text->assign(last_suggestion_);
-    // Track the url even if we're not going to update. This is important as
-    // when we get the suggest text we set user_text_ to the new suggest text,
-    // but yet the url is much different.
-    url_ = url;
-    return false;
-  }
-
-  url_ = url;
-  user_text_ = new_user_text;
-  verbatim_ = verbatim;
-  last_suggestion_.clear();
-  needs_reload_ = false;
-
-  bool created_preview_contents = preview_contents_.get() == NULL;
-  if (created_preview_contents)
-    CreatePreviewContents(tab_contents);
-
-  // Carry over the user agent override setting to the new entry.
-  content::NavigationEntry* entry =
-      tab_contents->web_contents()->GetController().GetActiveEntry();
-  bool override_user_agent = entry && entry->GetIsOverridingUserAgent();
-
-  if (template_url) {
-    DCHECK(template_url_id_ == template_url->id());
-    if (!created_preview_contents) {
-      if (is_determining_if_page_supports_instant()) {
-        // The page hasn't loaded yet. Note it, but send down the text anyway.
-        frame_load_observer_->set_text(user_text_);
-        frame_load_observer_->set_verbatim(verbatim);
-        preview_tab_contents_delegate_->set_user_typed_before_load();
-      }
-      // TODO: support real cursor position.
-      int text_length = static_cast<int>(user_text_.size());
-      RenderViewHost* host =
-          preview_contents_->web_contents()->GetRenderViewHost();
-      host->Send(new ChromeViewMsg_SearchBoxChange(
-          host->GetRoutingID(),
-          user_text_,
-          verbatim,
-          text_length,
-          text_length));
-
-      string16 complete_suggested_text_lower = base::i18n::ToLower(
-          complete_suggested_text_);
-      string16 user_text_lower = base::i18n::ToLower(user_text_);
-      if (!verbatim &&
-          complete_suggested_text_lower.size() > user_text_lower.size() &&
-          !complete_suggested_text_lower.compare(0, user_text_lower.size(),
-                                                 user_text_lower)) {
-        *suggested_text = last_suggestion_ =
-            complete_suggested_text_.substr(user_text_.size());
-      }
-    } else {
-      LoadInstantURL(template_url, transition_type, user_text_, verbatim,
-          override_user_agent);
-    }
-  } else {
-    DCHECK(template_url_id_ == 0);
-    preview_tab_contents_delegate_->PrepareForNewLoad();
-    frame_load_observer_.reset(NULL);
-
-    preview_contents_->web_contents()->GetController().
-        LoadURLWithUserAgentOverride(url_, content::Referrer(), transition_type,
-            false, std::string(), override_user_agent);
-  }
-  return true;
+void InstantLoader::Update(const std::string& user_text, bool verbatim) {
+  // TODO: Support real cursor position.
+  content::RenderViewHost* rvh =
+      preview_contents_->web_contents()->GetRenderViewHost();
+  rvh->Send(new ChromeViewMsg_SearchBoxChange(rvh->GetRoutingID(), user_text,
+                    verbatim, user_text.size(), user_text.size()));
 }
 
 void InstantLoader::SetOmniboxBounds(const gfx::Rect& bounds) {
-  if (omnibox_bounds_ == bounds)
-    return;
-
-  // Don't update the page while the mouse is down. http://crbug.com/71952
-  if (IsMouseDownFromActivate())
-    return;
-
-  omnibox_bounds_ = bounds;
-  if (preview_contents_.get() && is_showing_instant() &&
-      !is_determining_if_page_supports_instant()) {
-    // Updating the bounds is rather expensive, and because of the async nature
-    // of the omnibox the bounds can dance around a bit. Delay the update in
-    // hopes of things settling down. To avoid hiding results we grow
-    // immediately, but delay shrinking.
-    update_bounds_timer_.Stop();
-    if (omnibox_bounds_.height() > last_omnibox_bounds_.height()) {
-      SendBoundsToPage(false);
-    } else {
-      update_bounds_timer_.Start(FROM_HERE,
-          base::TimeDelta::FromMilliseconds(kUpdateBoundsDelayMS),
-          this, &InstantLoader::ProcessBoundsChange);
-    }
-  }
+  content::RenderViewHost* rvh =
+      preview_contents_->web_contents()->GetRenderViewHost();
+  rvh->Send(new ChromeViewMsg_SearchBoxResize(rvh->GetRoutingID(), bounds));
 }
 
-bool InstantLoader::IsMouseDownFromActivate() {
-  return preview_tab_contents_delegate_.get() &&
-      preview_tab_contents_delegate_->is_mouse_down_from_activate();
-}
-
-TabContents* InstantLoader::ReleasePreviewContents(
-    InstantCommitType type,
-    TabContents* tab_contents) {
-  if (!preview_contents_.get())
-    return NULL;
-
-  // FrameLoadObserver is only used for instant results, and instant results are
-  // only committed if active (when the FrameLoadObserver isn't installed).
-  DCHECK(type == INSTANT_COMMIT_DESTROY || !frame_load_observer_.get());
-
-  if (type != INSTANT_COMMIT_DESTROY && is_showing_instant()) {
-    RenderViewHost* host =
-        preview_contents_->web_contents()->GetRenderViewHost();
-    if (type == INSTANT_COMMIT_FOCUS_LOST) {
-      host->Send(new ChromeViewMsg_SearchBoxCancel(host->GetRoutingID()));
-    } else {
-      host->Send(new ChromeViewMsg_SearchBoxSubmit(
-          host->GetRoutingID(), user_text_,
-          type == INSTANT_COMMIT_PRESSED_ENTER));
-    }
+TabContents* InstantLoader::ReleasePreviewContents(InstantCommitType type,
+                                                   const std::string& text) {
+  content::RenderViewHost* rvh =
+      preview_contents_->web_contents()->GetRenderViewHost();
+  if (type == INSTANT_COMMIT_PRESSED_ENTER) {
+    rvh->Send(new ChromeViewMsg_SearchBoxSubmit(rvh->GetRoutingID(), text));
+  } else {
+    rvh->Send(new ChromeViewMsg_SearchBoxCancel(rvh->GetRoutingID(), text));
   }
-  omnibox_bounds_ = gfx::Rect();
-  last_omnibox_bounds_ = gfx::Rect();
-  GURL url;
-  url.Swap(&url_);
-  user_text_.clear();
-  complete_suggested_text_.clear();
-  if (preview_contents_.get()) {
-    if (type != INSTANT_COMMIT_DESTROY) {
-      if (template_url_id_) {
-        // The URL used during instant is mostly gibberish, and not something
-        // we'll parse and match as a past search. Set it to something we can
-        // parse.
-        preview_tab_contents_delegate_->SetLastHistoryURLAndPrune(url);
-      }
-      preview_tab_contents_delegate_->CommitHistory(template_url_id_ != 0);
-    }
-    if (preview_contents_->web_contents()->GetRenderWidgetHostView()) {
-#if defined(OS_MACOSX)
-      preview_contents_->web_contents()->GetRenderWidgetHostView()->
-          SetTakesFocusOnlyOnMouseDown(false);
-      registrar_.Remove(
-          this,
-          content::NOTIFICATION_RENDER_VIEW_HOST_CHANGED,
-          content::Source<NavigationController>(
-              &preview_contents_->web_contents()->GetController()));
-#endif
-    }
-    preview_contents_->web_contents()->SetDelegate(NULL);
-    ready_ = false;
-  }
-  update_bounds_timer_.Stop();
-  AddPreviewUsageForHistogram(template_url_id_,
-      type == INSTANT_COMMIT_DESTROY ? PREVIEW_DELETED : PREVIEW_COMMITTED,
-      group_);
-  if (type != INSTANT_COMMIT_DESTROY) {
-    base::Histogram* histogram = base::LinearHistogram::FactoryGet(
-        "Instant.SessionStorageNamespace" + group_, 1, 2, 3,
-        base::Histogram::kUmaTargetedHistogramFlag);
-    histogram->Add(tab_contents == NULL || session_storage_namespace_ ==
-        GetSessionStorageNamespace(tab_contents));
-    // Now that the ownership is being passed to the caller, the thumbnailer
-    // needs to resume taking thumbnails.
-    if (preview_contents_->thumbnail_generator())
-      preview_contents_->thumbnail_generator()->set_enabled(true);
-  }
-  session_storage_namespace_ = NULL;
+  CleanupPreviewContents();
   return preview_contents_.release();
 }
 
-bool InstantLoader::ShouldCommitInstantOnMouseUp() {
-  return delegate_->ShouldCommitInstantOnMouseUp();
+bool InstantLoader::IsMouseDownFromActivate() const {
+  return preview_delegate_->is_mouse_down_from_activate();
 }
 
-void InstantLoader::CommitInstantLoader() {
-  delegate_->CommitInstantLoader(this);
-}
-
-void InstantLoader::MaybeLoadInstantURL(TabContents* tab_contents,
-                                        const TemplateURL* template_url) {
-  DCHECK(template_url_id_ == template_url->id());
-
-  // If we already have a |preview_contents_|, future search queries will be
-  // issued into it (see the "if (!created_preview_contents)" block in |Update|
-  // above), so there is no need to load the |template_url|'s instant URL.
-  if (preview_contents_.get())
-    return;
-
-  // Carry over the user agent override setting to the new entry.
-  content::NavigationEntry* entry =
-      tab_contents->web_contents()->GetController().GetActiveEntry();
-  bool override_user_agent = entry && entry->GetIsOverridingUserAgent();
-
-  CreatePreviewContents(tab_contents);
-  LoadInstantURL(template_url, content::PAGE_TRANSITION_GENERATED, string16(),
-                 true, override_user_agent);
-}
-
-bool InstantLoader::IsNavigationPending() const {
-  return preview_contents_.get() &&
-      preview_contents_->web_contents()->GetController().GetPendingEntry();
-}
-
+#if defined(OS_MACOSX)
 void InstantLoader::Observe(int type,
                             const content::NotificationSource& source,
                             const content::NotificationDetails& details) {
-#if defined(OS_MACOSX)
   if (type == content::NOTIFICATION_RENDER_VIEW_HOST_CHANGED) {
-    if (preview_contents_->web_contents()->GetRenderWidgetHostView()) {
-      preview_contents_->web_contents()->GetRenderWidgetHostView()->
-          SetTakesFocusOnlyOnMouseDown(true);
+    if (content::RenderWidgetHostView* rwhv =
+            preview_contents_->web_contents()->GetRenderWidgetHostView()) {
+      rwhv->SetTakesFocusOnlyOnMouseDown(true);
     }
     return;
   }
+  NOTREACHED();
+}
 #endif
-  if (type == content::NOTIFICATION_NAV_ENTRY_COMMITTED) {
-    content::LoadCommittedDetails* load_details =
-        content::Details<content::LoadCommittedDetails>(details).ptr();
-    if (load_details->is_main_frame) {
-      if (load_details->http_status_code == kHostBlacklistStatusCode) {
-        delegate_->AddToBlacklist(this, load_details->entry->GetURL());
-      } else {
-        SetHTTPStatusOK(load_details->http_status_code == 200);
-      }
-    }
-    return;
+
+void InstantLoader::SetupPreviewContents() {
+  content::WebContents* new_contents = preview_contents_->web_contents();
+  WebContentsDelegateImpl* new_delegate = preview_delegate_.get();
+  new_contents->SetDelegate(new_delegate);
+
+  // Disable popups and such (mainly to avoid losing focus and committing the
+  // preview prematurely).
+  preview_contents_->blocked_content_tab_helper()->SetAllContentsBlocked(true);
+  preview_contents_->constrained_window_tab_helper()->set_delegate(
+                                                          new_delegate);
+  preview_contents_->content_settings()->SetPopupsBlocked(true);
+  preview_contents_->core_tab_helper()->set_delegate(new_delegate);
+  if (ThumbnailGenerator* tg = preview_contents_->thumbnail_generator())
+    tg->set_enabled(false);
+
+#if defined(OS_MACOSX)
+  // If |preview_contents_| does not currently have a RWHV, we will call
+  // |SetTakesFocusOnlyOnMouseDown| as a result of the RENDER_VIEW_HOST_CHANGED
+  // notification.
+  if (content::RenderWidgetHostView* rwhv =
+          new_contents->GetRenderWidgetHostView()) {
+    rwhv->SetTakesFocusOnlyOnMouseDown(true);
   }
-
-  NOTREACHED() << "Got a notification we didn't register for.";
+  registrar_.Add(this, content::NOTIFICATION_RENDER_VIEW_HOST_CHANGED,
+                 content::Source<content::NavigationController>(
+                     &new_contents->GetController()));
+#endif
 }
 
-void InstantLoader::SetCompleteSuggestedText(
-    const string16& complete_suggested_text,
-    InstantCompleteBehavior behavior) {
-  if (!is_showing_instant()) {
-    // We're not trying to use the instant API with this page. Ignore it.
-    return;
+void InstantLoader::CleanupPreviewContents() {
+  content::WebContents* old_contents = preview_contents_->web_contents();
+  old_contents->SetDelegate(NULL);
+
+  preview_contents_->blocked_content_tab_helper()->SetAllContentsBlocked(false);
+  preview_contents_->constrained_window_tab_helper()->set_delegate(NULL);
+  preview_contents_->content_settings()->SetPopupsBlocked(false);
+  preview_contents_->core_tab_helper()->set_delegate(NULL);
+  if (ThumbnailGenerator* tg = preview_contents_->thumbnail_generator())
+    tg->set_enabled(true);
+
+#if defined(OS_MACOSX)
+  if (content::RenderWidgetHostView* rwhv =
+          old_contents->GetRenderWidgetHostView()) {
+    rwhv->SetTakesFocusOnlyOnMouseDown(false);
   }
-
-  ShowPreview();
-
-  if (complete_suggested_text == complete_suggested_text_)
-    return;
-
-  if (verbatim_) {
-    // Don't show suggest results for verbatim queries.
-    return;
-  }
-
-  string16 user_text_lower = base::i18n::ToLower(user_text_);
-  string16 complete_suggested_text_lower = base::i18n::ToLower(
-      complete_suggested_text);
-  last_suggestion_.clear();
-  if (user_text_lower.compare(0, user_text_lower.size(),
-                              complete_suggested_text_lower,
-                              0, user_text_lower.size())) {
-    // The user text no longer contains the suggested text, ignore it.
-    complete_suggested_text_.clear();
-    delegate_->SetSuggestedTextFor(this, string16(), behavior);
-    return;
-  }
-
-  complete_suggested_text_ = complete_suggested_text;
-  if (behavior == INSTANT_COMPLETE_NOW) {
-    // We are effectively showing complete_suggested_text_ now. Update
-    // user_text_ so we don't notify the page again if Update happens to be
-    // invoked (which is more than likely if this callback completes before the
-    // omnibox is done).
-    string16 suggestion = complete_suggested_text_.substr(user_text_.size());
-    user_text_ = complete_suggested_text_;
-    delegate_->SetSuggestedTextFor(this, suggestion, behavior);
-  } else {
-    DCHECK((behavior == INSTANT_COMPLETE_DELAYED) ||
-           (behavior == INSTANT_COMPLETE_NEVER));
-    last_suggestion_ = complete_suggested_text_.substr(user_text_.size());
-    delegate_->SetSuggestedTextFor(this, last_suggestion_, behavior);
-  }
-}
-
-void InstantLoader::PreviewPainted() {
-  // If instant is supported then we wait for the first suggest result before
-  // showing the page.
-  if (!template_url_id_)
-    ShowPreview();
-}
-
-void InstantLoader::SetHTTPStatusOK(bool is_ok) {
-  if (is_ok == http_status_ok_)
-    return;
-
-  http_status_ok_ = is_ok;
-  if (ready_)
-    delegate_->InstantStatusChanged(this);
-}
-
-void InstantLoader::ShowPreview() {
-  if (!ready_) {
-    ready_ = true;
-    delegate_->InstantStatusChanged(this);
-    AddPreviewUsageForHistogram(template_url_id_, PREVIEW_SHOWN, group_);
-  }
-}
-
-void InstantLoader::PageFinishedLoading() {
-  frame_load_observer_.reset();
-
-  // Send the bounds of the omnibox down now.
-  SendBoundsToPage(false);
-
-  // Wait for the user input before showing, this way the page should be up to
-  // date by the time we show it.
-  AddPreviewUsageForHistogram(template_url_id_, PREVIEW_LOADED, group_);
-}
-
-// TODO(tonyg): This method only fires when the omnibox bounds change. It also
-// needs to fire when the preview bounds change (e.g. open/close info bar).
-gfx::Rect InstantLoader::GetOmniboxBoundsInTermsOfPreview() {
-  gfx::Rect preview_bounds(delegate_->GetInstantBounds());
-  gfx::Rect intersection(omnibox_bounds_.Intersect(preview_bounds));
-
-  // Translate into window's coordinates.
-  if (!intersection.IsEmpty()) {
-    intersection.Offset(-preview_bounds.origin().x(),
-                        -preview_bounds.origin().y());
-  }
-
-  // In the current Chrome UI, these must always be true so they sanity check
-  // the above operations. In a future UI, these may be removed or adjusted.
-  // There is no point in sanity-checking |intersection.y()| because the omnibox
-  // can be placed anywhere vertically relative to the preview (for example, in
-  // Mac fullscreen mode, the omnibox is entirely enclosed by the preview
-  // bounds).
-  DCHECK_LE(0, intersection.x());
-  DCHECK_LE(0, intersection.width());
-  DCHECK_LE(0, intersection.height());
-
-  return intersection;
-}
-
-void InstantLoader::PageDoesntSupportInstant(bool needs_reload) {
-  frame_load_observer_.reset(NULL);
-
-  delegate_->InstantLoaderDoesntSupportInstant(this);
-
-  AddPreviewUsageForHistogram(template_url_id_, PREVIEW_LOADED, group_);
-}
-
-void InstantLoader::ProcessBoundsChange() {
-  SendBoundsToPage(false);
-}
-
-void InstantLoader::SendBoundsToPage(bool force_if_waiting) {
-  if (last_omnibox_bounds_ == omnibox_bounds_)
-    return;
-
-  if (preview_contents_.get() && is_showing_instant() &&
-      (force_if_waiting || !is_determining_if_page_supports_instant())) {
-    last_omnibox_bounds_ = omnibox_bounds_;
-    RenderViewHost* host =
-        preview_contents_->web_contents()->GetRenderViewHost();
-    host->Send(new ChromeViewMsg_SearchBoxResize(
-        host->GetRoutingID(), GetOmniboxBoundsInTermsOfPreview()));
-  }
+  registrar_.Remove(this, content::NOTIFICATION_RENDER_VIEW_HOST_CHANGED,
+                    content::Source<content::NavigationController>(
+                        &old_contents->GetController()));
+#endif
 }
 
 void InstantLoader::ReplacePreviewContents(TabContents* old_tc,
                                            TabContents* new_tc) {
   DCHECK(old_tc == preview_contents_);
-  // We release here without deleting so that the caller still has reponsibility
-  // for deleting the TabContents.
+  CleanupPreviewContents();
+  // We release here without deleting so that the caller still has the
+  // responsibility for deleting the TabContents.
   ignore_result(preview_contents_.release());
   preview_contents_.reset(new_tc);
-  session_storage_namespace_ = GetSessionStorageNamespace(new_tc);
-
-  // Make sure the new preview contents acts like the old one.
-  SetupPreviewContents(old_tc);
-
-  // Cleanup the old preview contents.
-  old_tc->constrained_window_tab_helper()->set_delegate(NULL);
-  old_tc->core_tab_helper()->set_delegate(NULL);
-  old_tc->web_contents()->SetDelegate(NULL);
-
-#if defined(OS_MACOSX)
-  registrar_.Remove(
-      this,
-      content::NOTIFICATION_RENDER_VIEW_HOST_CHANGED,
-      content::Source<NavigationController>(
-          &old_tc->web_contents()->GetController()));
-#endif
-  registrar_.Remove(
-      this,
-      content::NOTIFICATION_NAV_ENTRY_COMMITTED,
-      content::Source<NavigationController>(
-          &old_tc->web_contents()->GetController()));
-
-  // We prerendered so we should be ready to show. If we're ready, swap in
-  // immediately, otherwise show the preview as normal.
-  if (ready_)
-    delegate_->SwappedTabContents(this);
-  else
-    ShowPreview();
+  SetupPreviewContents();
+  loader_delegate_->SwappedTabContents(this);
 }
-
-void InstantLoader::SetupPreviewContents(TabContents* tab_contents) {
-  preview_contents_->web_contents()->SetDelegate(
-      preview_tab_contents_delegate_.get());
-  preview_contents_->blocked_content_tab_helper()->SetAllContentsBlocked(true);
-  preview_contents_->constrained_window_tab_helper()->set_delegate(
-      preview_tab_contents_delegate_.get());
-  preview_contents_->core_tab_helper()->set_delegate(
-      preview_tab_contents_delegate_.get());
-  // Disables thumbnailing while the web contents is shown as preview to avoid
-  // generating unnecessary thumbnails.
-  if (preview_contents_->thumbnail_generator())
-    preview_contents_->thumbnail_generator()->set_enabled(false);
-
-#if defined(OS_MACOSX)
-  // If |preview_contents_| does not currently have a RWHV, we will call
-  // SetTakesFocusOnlyOnMouseDown() as a result of the
-  // RENDER_VIEW_HOST_CHANGED notification.
-  if (preview_contents_->web_contents()->GetRenderWidgetHostView()) {
-    preview_contents_->web_contents()->GetRenderWidgetHostView()->
-        SetTakesFocusOnlyOnMouseDown(true);
-  }
-  registrar_.Add(
-      this,
-      content::NOTIFICATION_RENDER_VIEW_HOST_CHANGED,
-      content::Source<NavigationController>(
-          &preview_contents_->web_contents()->GetController()));
-#endif
-
-  registrar_.Add(
-      this,
-      content::NOTIFICATION_NAV_ENTRY_COMMITTED,
-      content::Source<NavigationController>(
-          &preview_contents_->web_contents()->GetController()));
-
-  gfx::Rect tab_bounds;
-  tab_contents->web_contents()->GetView()->GetContainerBounds(&tab_bounds);
-  preview_contents_->web_contents()->GetView()->SizeContents(tab_bounds.size());
-
-  // Carry over the user agent override string.
-  const std::string& override =
-      tab_contents->web_contents()->GetUserAgentOverride();
-  preview_contents_->web_contents()->SetUserAgentOverride(override);
-}
-
-void InstantLoader::CreatePreviewContents(TabContents* tab_contents) {
-  WebContents* new_contents = WebContents::Create(
-      tab_contents->profile(), NULL, MSG_ROUTING_NONE, NULL, NULL);
-  preview_contents_.reset(new TabContents(new_contents));
-  AddPreviewUsageForHistogram(template_url_id_, PREVIEW_CREATED, group_);
-  session_storage_namespace_ = GetSessionStorageNamespace(tab_contents);
-  preview_tab_contents_delegate_.reset(new WebContentsDelegateImpl(this));
-  SetupPreviewContents(tab_contents);
-
-  // TODO(beng): investigate if we can avoid this and instead rely on the
-  //             visibility of the WebContentsView
-  preview_contents_->web_contents()->WasRestored();
-}
-
-void InstantLoader::LoadInstantURL(const TemplateURL* template_url,
-                                   content::PageTransition transition_type,
-                                   const string16& user_text,
-                                   bool verbatim,
-                                   bool override_user_agent) {
-  preview_tab_contents_delegate_->PrepareForNewLoad();
-
-  // Load the instant URL. We don't reflect the url we load in url() as
-  // callers expect that we're loading the URL they tell us to.
-  //
-  // This uses an empty string for the replacement text as the url doesn't
-  // really have the search params, but we need to use the replace
-  // functionality so that embeded tags (like {google:baseURL}) are escaped
-  // correctly.
-  // TODO(sky): having to use a replaceable url is a bit of a hack here.
-  GURL instant_url(template_url->instant_url_ref().ReplaceSearchTerms(
-      TemplateURLRef::SearchTermsArgs(string16())));
-  CommandLine* cl = CommandLine::ForCurrentProcess();
-  if (cl->HasSwitch(switches::kInstantURL))
-    instant_url = GURL(cl->GetSwitchValueASCII(switches::kInstantURL));
-
-  preview_contents_->web_contents()->GetController().
-      LoadURLWithUserAgentOverride(instant_url, content::Referrer(),
-          transition_type, false, std::string(), override_user_agent);
-
-  RenderViewHost* host = preview_contents_->web_contents()->GetRenderViewHost();
-  preview_contents_->web_contents()->WasHidden();
-
-  // If user_text is empty, this must be a preload of the search homepage. In
-  // that case, send down a SearchBoxResize message, which will switch the page
-  // to "search results" UI. This avoids flicker when the page is shown with
-  // results. In addition, we don't want the page accidentally causing the
-  // preloaded page to be displayed yet (by calling setSuggestions), so don't
-  // send a SearchBoxChange message.
-  if (user_text.empty()) {
-    host->Send(new ChromeViewMsg_SearchBoxResize(
-        host->GetRoutingID(), GetOmniboxBoundsInTermsOfPreview()));
-  } else {
-    host->Send(new ChromeViewMsg_SearchBoxChange(
-        host->GetRoutingID(), user_text, verbatim, 0, 0));
-  }
-
-  frame_load_observer_.reset(new FrameLoadObserver(
-      this, preview_contents()->web_contents(), user_text, verbatim));
-}