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

[sky, 2012/07/19 17:55:19]

|preview_contents_|

[Jered, 2012/07/19 22:01:33]

Done.

+  // 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();

[sky, 2012/07/19 17:55:19]

These are expensive operations and should be moved to an Init methods.

[Jered, 2012/07/19 22:01:33]

Done.

+  // This HTTP header and value are set on loads that originate from instant.
+  const char* const kInstantHeader = "X-Purpose";
+  const char* const kInstantHeaderValue = "Instant";
+  preview_contents_->web_contents()->GetController().LoadURL(instant_url,
+      content::Referrer(), content::PAGE_TRANSITION_GENERATED,
+      base::StringPrintf("%s: %s", kInstantHeader, kInstantHeaderValue));
+  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) {

[sky, 2012/07/19 17:55:19]

This should take string16. If it needs to convert to utf8 for the messages, do
it here.

[Jered, 2012/07/19 22:01:33]

Done.

+  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();
-}
-
-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();
+bool InstantLoader::IsMouseDownFromActivate() const {
+  return preview_delegate_->is_mouse_down_from_activate();
 }
 
 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;
-  }
-
-  NOTREACHED() << "Got a notification we didn't register for.";
 }
 
-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::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);
   }
-
-  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);
-  }
+  registrar_.Add(this, content::NOTIFICATION_RENDER_VIEW_HOST_CHANGED,
+                 content::Source<content::NavigationController>(
+                     &new_contents->GetController()));
+#endif
 }
 
-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::CleanupPreviewContents() {
+  content::WebContents* old_contents = preview_contents_->web_contents();
+  old_contents->SetDelegate(NULL);
 
-void InstantLoader::SetHTTPStatusOK(bool is_ok) {
-  if (is_ok == http_status_ok_)
-    return;
+  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);
 
-  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_);
+#if defined(OS_MACOSX)
+  if (content::RenderWidgetHostView* rwhv =
+          old_contents->GetRenderWidgetHostView()) {
+    rwhv->SetTakesFocusOnlyOnMouseDown(false);
   }
-}
-
-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));
-}