Adds support for showing the match preview on views. It's behind the

flag --enable-match-preview. There is still a lot of details to get it
working good enough, but this is a good point to check some stuff in.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/3105004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@55665 0039d316-1c4b-4281-b951-d872f2087c98

17 files changed, 602 insertions, 45 deletions

diff --git a/chrome/browser/browser.cc b/chrome/browser/browser.cc
index 83c6c48..6083fb0 100644
--- a/chrome/browser/browser.cc
+++ b/chrome/browser/browser.cc
@@ -70,6 +70,7 @@
 #include "chrome/browser/sync/sync_ui_util.h"
 #include "chrome/browser/tab_closeable_state_watcher.h"
 #include "chrome/browser/tab_contents/interstitial_page.h"
+#include "chrome/browser/tab_contents/match_preview.h"
 #include "chrome/browser/tab_contents/navigation_controller.h"
 #include "chrome/browser/tab_contents/navigation_entry.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
@@ -2944,6 +2945,16 @@ void Browser::ContentTypeChanged(TabContents* source) {
     UpdateZoomCommandsForTabState();
 }
 
+void Browser::CommitMatchPreview(TabContents* source) {
+  int index = tabstrip_model_.GetIndexOfTabContents(source);
+  DCHECK_NE(-1, index);
+  TabContents* preview_contents =
+      source->match_preview()->ReleasePreviewContents();
+  // TabStripModel takes ownership of preview_contents.
+  tabstrip_model_.ReplaceTabContentsAt(
+      index, preview_contents, TabStripModelObserver::REPLACE_MATCH_PREVIEW);
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 // Browser, SelectFileDialog::Listener implementation:
 
diff --git a/chrome/browser/browser.h b/chrome/browser/browser.h
index 1041735..0a7c0ab 100644
--- a/chrome/browser/browser.h
+++ b/chrome/browser/browser.h
@@ -741,6 +741,7 @@ class Browser : public TabStripModelDelegate,
                                        int32 page_id);
   virtual Browser* GetBrowser();
   virtual void ContentTypeChanged(TabContents* source);
+  virtual void CommitMatchPreview(TabContents* source);
 
   // Overridden from SelectFileDialog::Listener:
   virtual void FileSelected(const FilePath& path, int index, void* params);
diff --git a/chrome/browser/tab_contents/match_preview.cc b/chrome/browser/tab_contents/match_preview.cc
new file mode 100644
index 0000000..3c0c43e
--- /dev/null
+++ b/chrome/browser/tab_contents/match_preview.cc
@@ -0,0 +1,192 @@
+// Copyright (c) 2010 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/tab_contents/match_preview.h"
+
+#include <algorithm>
+
+#include "base/command_line.h"
+#include "chrome/browser/tab_contents/navigation_controller.h"
+#include "chrome/browser/tab_contents/navigation_entry.h"
+#include "chrome/browser/tab_contents/tab_contents.h"
+#include "chrome/browser/tab_contents/tab_contents_delegate.h"
+#include "chrome/common/chrome_switches.h"
+#include "chrome/common/notification_service.h"
+#include "chrome/common/page_transition_types.h"
+#include "chrome/common/renderer_preferences.h"
+#include "ipc/ipc_message.h"
+
+class MatchPreview::TabContentsDelegateImpl : public TabContentsDelegate {
+ public:
+  explicit TabContentsDelegateImpl(MatchPreview* match_preview)
+      : match_preview_(match_preview) {
+  }
+
+  virtual void OpenURLFromTab(TabContents* source,
+                              const GURL& url, const GURL& referrer,
+                              WindowOpenDisposition disposition,
+                              PageTransition::Type transition) {}
+  virtual void NavigationStateChanged(const TabContents* source,
+                                      unsigned changed_flags) {}
+  virtual void AddNewContents(TabContents* source,
+                              TabContents* new_contents,
+                              WindowOpenDisposition disposition,
+                              const gfx::Rect& initial_pos,
+                              bool user_gesture) {}
+  virtual void ActivateContents(TabContents* contents) {
+    match_preview_->CommitCurrentPreview();
+  }
+  virtual void LoadingStateChanged(TabContents* source) {}
+  virtual void CloseContents(TabContents* source) {}
+  virtual void MoveContents(TabContents* source, const gfx::Rect& pos) {}
+  virtual void DetachContents(TabContents* source) {}
+  virtual bool IsPopup(const TabContents* source) const {
+    return false;
+  }
+  virtual TabContents* GetConstrainingContents(TabContents* source) {
+    return NULL;
+  }
+  virtual void ToolbarSizeChanged(TabContents* source, bool is_animating) {}
+  virtual void URLStarredChanged(TabContents* source, bool starred) {}
+  virtual void UpdateTargetURL(TabContents* source, const GURL& url) {}
+  virtual void ContentsMouseEvent(
+      TabContents* source, const gfx::Point& location, bool motion) {}
+  virtual void ContentsZoomChange(bool zoom_in) {}
+  virtual void OnContentSettingsChange(TabContents* source) {}
+  virtual bool IsApplication() const { return false; }
+  virtual void ConvertContentsToApplication(TabContents* source) {}
+  virtual bool CanReloadContents(TabContents* source) const { return true; }
+  virtual gfx::Rect GetRootWindowResizerRect() const {
+    return match_preview_->host_->delegate() ?
+        match_preview_->host_->delegate()->GetRootWindowResizerRect() :
+        gfx::Rect();
+  }
+  virtual void ShowHtmlDialog(HtmlDialogUIDelegate* delegate,
+                              gfx::NativeWindow parent_window) {}
+  virtual void BeforeUnloadFired(TabContents* tab,
+                                 bool proceed,
+                                 bool* proceed_to_fire_unload) {}
+  virtual void ForwardMessageToExternalHost(const std::string& message,
+                                            const std::string& origin,
+                                            const std::string& target) {}
+  virtual bool IsExternalTabContainer() const { return false; }
+  virtual void SetFocusToLocationBar(bool select_all) {}
+  virtual void RenderWidgetShowing() {}
+  virtual ExtensionFunctionDispatcher* CreateExtensionFunctionDispatcher(
+      RenderViewHost* render_view_host,
+      const std::string& extension_id) {
+    return NULL;
+  }
+  virtual bool TakeFocus(bool reverse) { return false; }
+  virtual void SetTabContentBlocked(TabContents* contents, bool blocked) {}
+  virtual void TabContentsFocused(TabContents* tab_content) {
+    match_preview_->CommitCurrentPreview();
+  }
+  virtual int GetExtraRenderViewHeight() const { return 0; }
+  virtual bool CanDownload(int request_id) { return false; }
+  virtual void OnStartDownload(DownloadItem* download, TabContents* tab) {}
+  virtual bool HandleContextMenu(const ContextMenuParams& params) {
+    return false;
+  }
+  virtual bool ExecuteContextMenuCommand(int command) {
+    return false;
+  }
+  virtual void ConfirmAddSearchProvider(const TemplateURL* template_url,
+                                        Profile* profile) {}
+  virtual void ShowPageInfo(Profile* profile,
+                            const GURL& url,
+                            const NavigationEntry::SSLStatus& ssl,
+                            bool show_history) {}
+  virtual bool PreHandleKeyboardEvent(const NativeWebKeyboardEvent& event,
+                                      bool* is_keyboard_shortcut) {
+    return false;
+  }
+  virtual void HandleKeyboardEvent(const NativeWebKeyboardEvent& event) {}
+  virtual void ShowRepostFormWarningDialog(TabContents* tab_contents) {}
+  virtual void ShowContentSettingsWindow(ContentSettingsType content_type) {}
+  virtual void ShowCollectedCookiesDialog(TabContents* tab_contents) {}
+  virtual bool OnGoToEntryOffset(int offset) { return false; }
+  virtual bool ShouldAddNavigationsToHistory() const { return false; }
+  virtual void OnDidGetApplicationInfo(TabContents* tab_contents,
+                                       int32 page_id) {}
+  virtual Browser* GetBrowser() { return NULL; }
+  virtual gfx::NativeWindow GetFrameNativeWindow() {
+    return match_preview_->host_->delegate() ?
+        match_preview_->host_->delegate()->GetFrameNativeWindow() : NULL;
+  }
+  virtual void TabContentsCreated(TabContents* new_contents) {}
+  virtual bool infobars_enabled() { return false; }
+  virtual bool ShouldEnablePreferredSizeNotifications() { return false; }
+  virtual void UpdatePreferredSize(const gfx::Size& pref_size) {}
+  virtual void ContentTypeChanged(TabContents* source) {}
+
+ private:
+  MatchPreview* match_preview_;
+
+  DISALLOW_COPY_AND_ASSIGN(TabContentsDelegateImpl);
+};
+
+MatchPreview::MatchPreview(TabContents* host) : host_(host) {
+  delegate_.reset(new TabContentsDelegateImpl(this));
+}
+
+MatchPreview::~MatchPreview() {
+  // Delete the TabContents before the delegate as the TabContents holds a
+  // reference to the delegate.
+  preview_contents_.reset(NULL);
+}
+
+// static
+bool MatchPreview::IsEnabled() {
+  static bool enabled = false;
+  static bool checked = false;
+  if (!checked) {
+    checked = true;
+    enabled = CommandLine::ForCurrentProcess()->HasSwitch(
+        switches::kEnableMatchPreview);
+  }
+  return enabled;
+}
+
+void MatchPreview::Update(const GURL& url) {
+  if (url_ == url)
+    return;
+
+  url_ = url;
+
+  if (url_.is_empty() || !url_.is_valid()) {
+    DestroyPreviewContents();
+    return;
+  }
+
+  if (!preview_contents_.get()) {
+    preview_contents_.reset(
+        new TabContents(host_->profile(), NULL, MSG_ROUTING_NONE, NULL));
+    preview_contents_->set_delegate(delegate_.get());
+    NotificationService::current()->Notify(
+        NotificationType::MATCH_PREVIEW_TAB_CONTENTS_CREATED,
+        Source<TabContents>(host_),
+        NotificationService::NoDetails());
+  }
+
+  // TODO: figure out transition type.
+  preview_contents_->controller().LoadURL(url, GURL(),
+                                          PageTransition::GENERATED);
+}
+
+void MatchPreview::DestroyPreviewContents() {
+  url_ = GURL();
+  preview_contents_.reset(NULL);
+}
+
+void MatchPreview::CommitCurrentPreview() {
+  DCHECK(preview_contents_.get());
+  if (host_->delegate())
+    host_->delegate()->CommitMatchPreview(host_);
+}
+
+TabContents* MatchPreview::ReleasePreviewContents() {
+  url_ = GURL();
+  return preview_contents_.release();
+}
diff --git a/chrome/browser/tab_contents/match_preview.h b/chrome/browser/tab_contents/match_preview.h
new file mode 100644
index 0000000..cc6605b
--- /dev/null
+++ b/chrome/browser/tab_contents/match_preview.h
@@ -0,0 +1,80 @@
+// Copyright (c) 2010 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.
+
+#ifndef CHROME_BROWSER_TAB_CONTENTS_MATCH_PREVIEW_H_
+#define CHROME_BROWSER_TAB_CONTENTS_MATCH_PREVIEW_H_
+
+#include "base/basictypes.h"
+#include "base/scoped_ptr.h"
+#include "googleurl/src/gurl.h"
+
+class TabContents;
+
+// MatchPreview maintains a TabContents that is intended to give a preview of
+// a URL. MatchPreview is owned by TabContents.
+//
+// As the user types in the omnibox the LocationBar updates MatchPreview by
+// way of 'Update'. If the user does a gesture on the preview, say clicks a
+// link, the TabContentsDelegate of the hosting TabContents is notified with
+// CommitMatchPreview and the TabContents maintained by MatchPreview replaces
+// the current TabContents in the TabStripModel.
+//
+// At any time the TabContents maintained by MatchPreview may be destroyed by
+// way of 'DestroyPreviewContents'. Consumers of MatchPreview can detect the
+// preview TabContents was destroyed by observing TAB_CONTENTS_DESTROYED.
+//
+// Consumers of MatchPreview can detect a new TabContents was created by
+// MatchPreview by listening for MATCH_PREVIEW_TAB_CONTENTS_CREATED.
+class MatchPreview {
+ public:
+  explicit MatchPreview(TabContents* host);
+  ~MatchPreview();
+
+  // Is MatchPreview enabled?
+  static bool IsEnabled();
+
+  // Invoked as the user types in the omnibox with the url to navigate to.  If
+  // the url is empty and there is a preview TabContents it is destroyed. If url
+  // is non-empty and the preview TabContents has not been created it is
+  // created.
+  void Update(const GURL& url);
+
+  // Destroys the preview TabContents. Does nothing if the preview TabContents
+  // has not been created.
+  void DestroyPreviewContents();
+
+  // Invoked when the user does some gesture that should trigger making the
+  // current previewed page the permanent page.
+  void CommitCurrentPreview();
+
+  // Releases the preview TabContents passing ownership to the caller. This is
+  // intended to be called when the preview TabContents is committed.
+  TabContents* ReleasePreviewContents();
+
+  // The TabContents we're maintaining the preview for.
+  TabContents* host() { return host_; }
+
+  // The preview TabContents; may be null.
+  TabContents* preview_contents() { return preview_contents_.get(); }
+
+ private:
+  class TabContentsDelegateImpl;
+
+  // The url we're displaying.
+  GURL url_;
+
+  // The TabContents we're providing the preview for.
+  TabContents* host_;
+
+  // Delegate of the preview TabContents. Used to detect when the user does some
+  // gesture on the TabContents and the preview needs to be activated.
+  scoped_ptr<TabContentsDelegateImpl> delegate_;
+
+  // The preview TabContents; may be null.
+  scoped_ptr<TabContents> preview_contents_;
+
+  DISALLOW_COPY_AND_ASSIGN(MatchPreview);
+};
+
+#endif  // CHROME_BROWSER_TAB_CONTENTS_MATCH_PREVIEW_H_
diff --git a/chrome/browser/tab_contents/tab_contents.cc b/chrome/browser/tab_contents/tab_contents.cc
index 42da773..076ced4 100644
--- a/chrome/browser/tab_contents/tab_contents.cc
+++ b/chrome/browser/tab_contents/tab_contents.cc
@@ -69,6 +69,7 @@
 #include "chrome/browser/sessions/session_types.h"
 #include "chrome/browser/tab_contents/infobar_delegate.h"
 #include "chrome/browser/tab_contents/interstitial_page.h"
+#include "chrome/browser/tab_contents/match_preview.h"
 #include "chrome/browser/tab_contents/navigation_entry.h"
 #include "chrome/browser/tab_contents/provisional_load_details.h"
 #include "chrome/browser/tab_contents/tab_contents_delegate.h"
@@ -424,6 +425,9 @@ TabContents::TabContents(Profile* profile,
   // Set-up the showing of the omnibox search infobar if applicable.
   if (OmniboxSearchHint::IsEnabled(profile))
     omnibox_search_hint_.reset(new OmniboxSearchHint(this));
+
+  if (MatchPreview::IsEnabled())
+    match_preview_.reset(new MatchPreview(this));
 }
 
 TabContents::~TabContents() {
diff --git a/chrome/browser/tab_contents/tab_contents.h b/chrome/browser/tab_contents/tab_contents.h
index ab4cf56..ac73e96 100644
--- a/chrome/browser/tab_contents/tab_contents.h
+++ b/chrome/browser/tab_contents/tab_contents.h
@@ -68,6 +68,7 @@ class DownloadItem;
 class Extension;
 class InfoBarDelegate;
 class LoadNotificationDetails;
+class MatchPreview;
 class OmniboxSearchHint;
 class PasswordManager;
 class PluginInstaller;
@@ -160,6 +161,9 @@ class TabContents : public PageNavigator,
   // Returns the TabContentsSSLHelper, creating if it necessary.
   TabContentsSSLHelper* GetSSLHelper();
 
+  // Returns the MatchPreview. Returns NULL if MatchPreview is not enabled.
+  MatchPreview* match_preview() { return match_preview_.get(); }
+
   // Returns the SavePackage which manages the page saving job. May be NULL.
   SavePackage* save_package() const { return save_package_.get(); }
 
@@ -1261,6 +1265,8 @@ class TabContents : public PageNavigator,
   // See description in RenderViewHostDelegate::SetDisplayingPDFContent.
   bool displaying_pdf_content_;
 
+  scoped_ptr<MatchPreview> match_preview_;
+
   // ---------------------------------------------------------------------------
 
   DISALLOW_COPY_AND_ASSIGN(TabContents);
diff --git a/chrome/browser/tab_contents/tab_contents_delegate.cc b/chrome/browser/tab_contents/tab_contents_delegate.cc
index 30bee94..9c89cd3 100644
--- a/chrome/browser/tab_contents/tab_contents_delegate.cc
+++ b/chrome/browser/tab_contents/tab_contents_delegate.cc
@@ -167,5 +167,8 @@ void TabContentsDelegate::UpdatePreferredSize(const gfx::Size& pref_size) {
 void TabContentsDelegate::ContentTypeChanged(TabContents* source) {
 }
 
+void TabContentsDelegate::CommitMatchPreview(TabContents* source) {
+}
+
 TabContentsDelegate::~TabContentsDelegate() {
 }
diff --git a/chrome/browser/tab_contents/tab_contents_delegate.h b/chrome/browser/tab_contents/tab_contents_delegate.h
index 9b2230e..a6b2597 100644
--- a/chrome/browser/tab_contents/tab_contents_delegate.h
+++ b/chrome/browser/tab_contents/tab_contents_delegate.h
@@ -277,6 +277,11 @@ class TabContentsDelegate : public AutomationResourceRoutingDelegate {
   // PDF using the internal PDF plugin.
   virtual void ContentTypeChanged(TabContents* source);
 
+  // Sent when the user does a gesture that results in committing the match
+  // preview. The delegate should replace |source| with the |source|'s match
+  // preview TabContents.
+  virtual void CommitMatchPreview(TabContents* source);
+
  protected:
   virtual ~TabContentsDelegate();
 };
diff --git a/chrome/browser/tabs/tab_strip_model.cc b/chrome/browser/tabs/tab_strip_model.cc
index 8ac8fc4..269de35 100644
--- a/chrome/browser/tabs/tab_strip_model.cc
+++ b/chrome/browser/tabs/tab_strip_model.cc
@@ -82,6 +82,13 @@ void TabStripModelObserver::TabReplacedAt(TabContents* old_contents,
                                           int index) {
 }
 
+void TabStripModelObserver::TabReplacedAt(TabContents* old_contents,
+                                          TabContents* new_contents,
+                                          int index,
+                                          TabReplaceType type) {
+  TabReplacedAt(old_contents, new_contents, index);
+}
+
 void TabStripModelObserver::TabPinnedStateChanged(TabContents* contents,
                                                   int index) {
 }
@@ -233,6 +240,13 @@ void TabStripModel::InsertTabContentsAt(int index,
     ChangeSelectedContentsFrom(selected_contents, index, false);
 }
 
+void TabStripModel::ReplaceTabContentsAt(
+    int index,
+    TabContents* new_contents,
+    TabStripModelObserver::TabReplaceType type) {
+  delete ReplaceTabContentsAtImpl(index, new_contents, type);
+}
+
 void TabStripModel::ReplaceNavigationControllerAt(
     int index, NavigationController* controller) {
   // This appears to be OK with no flicker since no redraw event
@@ -1043,14 +1057,10 @@ bool TabStripModel::ShouldMakePhantomOnClose(int index) {
 }
 
 void TabStripModel::MakePhantom(int index) {
-  TabContents* old_contents = GetContentsAt(index);
-  TabContents* new_contents = old_contents->CloneAndMakePhantom();
-
-  contents_data_[index]->contents = new_contents;
-
-  // And notify observers.
-  FOR_EACH_OBSERVER(TabStripModelObserver, observers_,
-                    TabReplacedAt(old_contents, new_contents, index));
+  // MakePhantom is called when the TabContents is being destroyed so we don't
+  // need to do anything with the returned value from ReplaceTabContentsAtImpl.
+  ReplaceTabContentsAtImpl(index, GetContentsAt(index)->CloneAndMakePhantom(),
+                           TabStripModelObserver::REPLACE_MADE_PHANTOM);
 
   if (selected_index_ == index && HasNonPhantomTabs()) {
     // Change the selection, otherwise we're going to force the phantom tab
@@ -1095,3 +1105,20 @@ bool TabStripModel::OpenerMatches(const TabContentsData* data,
                                   bool use_group) {
   return data->opener == opener || (use_group && data->group == opener);
 }
+
+TabContents* TabStripModel::ReplaceTabContentsAtImpl(
+    int index,
+    TabContents* new_contents,
+    TabStripModelObserver::TabReplaceType type) {
+  // TODO: this should reset group/opener of any tabs that point at
+  // old_contents.
+  DCHECK(ContainsIndex(index));
+
+  TabContents* old_contents = GetContentsAt(index);
+
+  contents_data_[index]->contents = new_contents;
+
+  FOR_EACH_OBSERVER(TabStripModelObserver, observers_,
+                    TabReplacedAt(old_contents, new_contents, index, type));
+  return old_contents;
+}
diff --git a/chrome/browser/tabs/tab_strip_model.h b/chrome/browser/tabs/tab_strip_model.h
index f26af59..542b27f 100644
--- a/chrome/browser/tabs/tab_strip_model.h
+++ b/chrome/browser/tabs/tab_strip_model.h
@@ -54,6 +54,18 @@ class TabStripModelObserver {
     ALL
   };
 
+  // Enum used by ReplaceTabContentsAt.
+  // TODO(sky): TabReplaceType should be declared outside the scope of
+  // the observer. I need to put all the enums in a namespace and cleanup this
+  // file.
+  enum TabReplaceType {
+    // The replace is the result of the tab being made phantom.
+    REPLACE_MADE_PHANTOM,
+
+    // The replace is the result of the match preview being committed.
+    REPLACE_MATCH_PREVIEW
+  };
+
   // A new TabContents was inserted into the TabStripModel at the specified
   // index. |foreground| is whether or not it was opened in the foreground
   // (selected).
@@ -100,8 +112,18 @@ class TabStripModelObserver {
   // The tab contents was replaced at the specified index. This is invoked when
   // a tab becomes phantom. See description of phantom tabs in class description
   // of TabStripModel for details.
+  // TODO(sky): nuke this in favor of the 4 arg variant.
+  virtual void TabReplacedAt(TabContents* old_contents,
+                             TabContents* new_contents,
+                             int index);
+
+  // The tab contents was replaced at the specified index. |type| describes
+  // the type of replace.
+  // This invokes TabReplacedAt with three args.
   virtual void TabReplacedAt(TabContents* old_contents,
-                             TabContents* new_contents, int index);
+                             TabContents* new_contents,
+                             int index,
+                             TabReplaceType type);
 
   // Invoked when the pinned state of a tab changes. This is not invoked if the
   // tab ends up moving as a result of the mini state changing.
@@ -433,6 +455,12 @@ class TabStripModel : public NotificationObserver {
   void ReplaceNavigationControllerAt(int index,
                                      NavigationController* controller);
 
+  // Replaces the tab contents at |index| with |new_contents|. |type| is passed
+  // to the observer. This deletes the TabContents currently at |index|.
+  void ReplaceTabContentsAt(int index,
+                            TabContents* new_contents,
+                            TabStripModelObserver::TabReplaceType type);
+
   // Detaches the TabContents at the specified index from this strip. The
   // TabContents is not destroyed, just removed from display. The caller is
   // responsible for doing something with it (e.g. stuffing it into another
@@ -725,6 +753,13 @@ class TabStripModel : public NotificationObserver {
                             const NavigationController* opener,
                             bool use_group);
 
+  // Does the work for ReplaceTabContentsAt returning the old TabContents.
+  // The caller owns the returned TabContents.
+  TabContents* ReplaceTabContentsAtImpl(
+      int index,
+      TabContents* new_contents,
+      TabStripModelObserver::TabReplaceType type);
+
   // Our delegate.
   TabStripModelDelegate* delegate_;
 
diff --git a/chrome/browser/views/frame/browser_view.cc b/chrome/browser/views/frame/browser_view.cc
index 3034a38..8c1189c 100644
--- a/chrome/browser/views/frame/browser_view.cc
+++ b/chrome/browser/views/frame/browser_view.cc
@@ -15,6 +15,8 @@
 #include "base/utf_string_conversions.h"
 #include "chrome/app/chrome_dll_resource.h"
 #include "chrome/browser/app_modal_dialog_queue.h"
+#include "chrome/browser/autocomplete/autocomplete_popup_model.h"
+#include "chrome/browser/autocomplete/autocomplete_popup_view.h"
 #include "chrome/browser/automation/ui_controls.h"
 #include "chrome/browser/bookmarks/bookmark_utils.h"
 #include "chrome/browser/browser_list.h"
@@ -27,6 +29,7 @@
 #include "chrome/browser/pref_service.h"
 #include "chrome/browser/profile.h"
 #include "chrome/browser/sessions/tab_restore_service.h"
+#include "chrome/browser/tab_contents/match_preview.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/browser/tab_contents/tab_contents_view.h"
 #include "chrome/browser/view_ids.h"
@@ -127,6 +130,71 @@ static gfx::NativeWindow GetNormalBrowserWindowForBrowser(Browser* browser,
 }
 #endif  // defined(OS_CHROMEOS)
 
+// ContentsContainer is responsible for managing the TabContents views.
+// ContentsContainer has up to two children: one for the currently active
+// TabContents and one for the match preview TabContents.
+class BrowserView::ContentsContainer : public views::View {
+ public:
+  ContentsContainer(BrowserView* browser_view, views::View* active)
+      : browser_view_(browser_view),
+        active_(active),
+        preview_(NULL) {
+    AddChildView(active_);
+  }
+
+  // Makes the preview view the active view and nulls out the old active view.
+  // It's assumed the caller will delete or remove the old active view
+  // separately.
+  void MakePreviewContentsActiveContents() {
+    active_ = preview_;
+    preview_ = NULL;
+    Layout();
+  }
+
+  // Sets the preview view. This does not delete the old.
+  void SetPreview(views::View* preview) {
+    if (preview == preview_)
+      return;
+
+    if (preview_)
+      RemoveChildView(preview_);
+    preview_ = preview;
+    if (preview_)
+      AddChildView(preview_);
+
+    Layout();
+  }
+
+  virtual void Layout() {
+    // The active view always gets the full bounds.
+    active_->SetBounds(0, 0, width(), height());
+
+    if (preview_) {
+      // The preview view gets the full width and is positioned beneath the
+      // bottom of the autocompleted popup.
+      int max_autocomplete_y = browser_view_->toolbar()->location_bar()->
+          location_entry()->model()->popup_model()->view()->GetMaxYCoordinate();
+      gfx::Point screen_origin;
+      views::View::ConvertPointToScreen(this, &screen_origin);
+      DCHECK_GT(max_autocomplete_y, screen_origin.y());
+      int preview_origin = max_autocomplete_y - screen_origin.y();
+      if (preview_origin < height()) {
+        preview_->SetBounds(0, preview_origin, width(),
+                            height() - preview_origin);
+      } else {
+        preview_->SetBounds(0, 0, 0, 0);
+      }
+    }
+  }
+
+ private:
+  BrowserView* browser_view_;
+  views::View* active_;
+  views::View* preview_;
+
+  DISALLOW_COPY_AND_ASSIGN(ContentsContainer);
+};
+
 ///////////////////////////////////////////////////////////////////////////////
 // BookmarkExtensionBackground, private:
 // This object serves as the views::Background object which is used to layout
@@ -416,6 +484,8 @@ BrowserView::BrowserView(Browser* browser)
       infobar_container_(NULL),
       contents_container_(NULL),
       devtools_container_(NULL),
+      preview_container_(NULL),
+      contents_(NULL),
       contents_split_(NULL),
       initialized_(false),
       ignore_layout_(true),
@@ -518,7 +588,7 @@ gfx::Rect BrowserView::GetToolbarBounds() const {
 }
 
 gfx::Rect BrowserView::GetClientAreaBounds() const {
-  gfx::Rect container_bounds = contents_container_->bounds();
+  gfx::Rect container_bounds = contents_->bounds();
   gfx::Point container_origin = container_bounds.origin();
   ConvertPointToView(this, GetParent(), &container_origin);
   container_bounds.set_origin(container_origin);
@@ -1320,12 +1390,36 @@ ToolbarView* BrowserView::GetToolbarView() const {
 void BrowserView::Observe(NotificationType type,
                           const NotificationSource& source,
                           const NotificationDetails& details) {
-  if (type == NotificationType::PREF_CHANGED &&
-      *Details<std::string>(details).ptr() == prefs::kShowBookmarkBar) {
-    if (MaybeShowBookmarkBar(browser_->GetSelectedTabContents()))
-      Layout();
-  } else {
-    NOTREACHED() << "Got a notification we didn't register for!";
+  switch (type.value) {
+    case NotificationType::PREF_CHANGED:
+      if (*Details<std::string>(details).ptr() == prefs::kShowBookmarkBar &&
+          MaybeShowBookmarkBar(browser_->GetSelectedTabContents())) {
+        Layout();
+      }
+      break;
+
+    case NotificationType::MATCH_PREVIEW_TAB_CONTENTS_CREATED:
+      if (Source<TabContents>(source).ptr() ==
+          browser_->GetSelectedTabContents()) {
+        ShowMatchPreview();
+      }
+      break;
+
+    case NotificationType::TAB_CONTENTS_DESTROYED: {
+      if (MatchPreview::IsEnabled()) {
+        TabContents* selected_contents = browser_->GetSelectedTabContents();
+        if (selected_contents &&
+            selected_contents->match_preview()->preview_contents() ==
+            Source<TabContents>(source).ptr()) {
+          HideMatchPreview();
+        }
+      }
+      break;
+    }
+
+    default:
+      NOTREACHED() << "Got a notification we didn't register for!";
+      break;
   }
 }
 
@@ -1360,34 +1454,29 @@ void BrowserView::TabSelectedAt(TabContents* old_contents,
                                 bool user_gesture) {
   DCHECK(old_contents != new_contents);
 
-  // Update various elements that are interested in knowing the current
-  // TabContents.
-
-  // When we toggle the NTP floating bookmarks bar and/or the info bar,
-  // we don't want any TabContents to be attached, so that we
-  // avoid an unnecessary resize and re-layout of a TabContents.
-  contents_container_->ChangeTabContents(NULL);
-  infobar_container_->ChangeTabContents(new_contents);
-  UpdateUIForContents(new_contents);
-  contents_container_->ChangeTabContents(new_contents);
+  ProcessTabSelected(new_contents, true);
+}
 
-  UpdateDevToolsForContents(new_contents);
-  // TODO(beng): This should be called automatically by ChangeTabContents, but I
-  //             am striving for parity now rather than cleanliness. This is
-  //             required to make features like Duplicate Tab, Undo Close Tab,
-  //             etc not result in sad tab.
-  new_contents->DidBecomeSelected();
-  if (BrowserList::GetLastActive() == browser_ &&
-      !browser_->tabstrip_model()->closing_all() && GetWindow()->IsVisible()) {
-    // We only restore focus if our window is visible, to avoid invoking blur
-    // handlers when we are eventually shown.
-    new_contents->view()->RestoreFocus();
+void BrowserView::TabReplacedAt(TabContents* old_contents,
+                                TabContents* new_contents,
+                                int index,
+                                TabStripModelObserver::TabReplaceType type) {
+  if (type != TabStripModelObserver::REPLACE_MATCH_PREVIEW ||
+      index != browser_->tabstrip_model()->selected_index()) {
+    return;
   }
 
-  // Update all the UI bits.
-  UpdateTitleBar();
-  UpdateToolbar(new_contents, true);
-  UpdateUIForContents(new_contents);
+  // Swap the 'active' and 'preview' and delete what was the active.
+  contents_->MakePreviewContentsActiveContents();
+  TabContentsContainer* old_container = contents_container_;
+  contents_container_ = preview_container_;
+  old_container->ChangeTabContents(NULL);
+  delete old_container;
+  preview_container_ = NULL;
+
+  // Update the UI for what was the preview contents and is now active. Pass in
+  // false to ProcessTabSelected as new_contents is already parented correctly.
+  ProcessTabSelected(new_contents, false);
 }
 
 void BrowserView::TabStripEmpty() {
@@ -1759,11 +1848,12 @@ void BrowserView::Init() {
   AddChildView(infobar_container_);
 
   contents_container_ = new TabContentsContainer;
+  contents_ = new ContentsContainer(this, contents_container_);
   devtools_container_ = new TabContentsContainer;
   devtools_container_->SetID(VIEW_ID_DEV_TOOLS_DOCKED);
   devtools_container_->SetVisible(false);
   contents_split_ = new views::SingleSplitView(
-      contents_container_,
+      contents_,
       devtools_container_,
       views::SingleSplitView::VERTICAL_SPLIT);
   contents_split_->SetID(VIEW_ID_CONTENTS_SPLIT);
@@ -1808,6 +1898,13 @@ void BrowserView::Init() {
 
   // We're now initialized and ready to process Layout requests.
   ignore_layout_ = false;
+
+  registrar_.Add(this,
+                 NotificationType::MATCH_PREVIEW_TAB_CONTENTS_CREATED,
+                 NotificationService::AllSources());
+  registrar_.Add(this,
+                 NotificationType::TAB_CONTENTS_DESTROYED,
+                 NotificationService::AllSources());
 }
 
 #if defined(OS_WIN)
@@ -2234,6 +2331,60 @@ void BrowserView::InitHangMonitor() {
 #endif
 }
 
+void BrowserView::ShowMatchPreview() {
+  if (!preview_container_)
+    preview_container_ = new TabContentsContainer();
+  contents_->SetPreview(preview_container_);
+  preview_container_->ChangeTabContents(
+      browser_->GetSelectedTabContents()->match_preview()->preview_contents());
+}
+
+void BrowserView::HideMatchPreview() {
+  if (!preview_container_)
+    return;
+
+  // The contents must be changed before SetPreview is invoked.
+  preview_container_->ChangeTabContents(NULL);
+  contents_->SetPreview(NULL);
+  delete preview_container_;
+  preview_container_ = NULL;
+}
+
+void BrowserView::ProcessTabSelected(TabContents* new_contents,
+                                     bool change_tab_contents) {
+
+  // Update various elements that are interested in knowing the current
+  // TabContents.
+
+  // When we toggle the NTP floating bookmarks bar and/or the info bar,
+  // we don't want any TabContents to be attached, so that we
+  // avoid an unnecessary resize and re-layout of a TabContents.
+  if (change_tab_contents)
+    contents_container_->ChangeTabContents(NULL);
+  infobar_container_->ChangeTabContents(new_contents);
+  UpdateUIForContents(new_contents);
+  if (change_tab_contents)
+    contents_container_->ChangeTabContents(new_contents);
+
+  UpdateDevToolsForContents(new_contents);
+  // TODO(beng): This should be called automatically by ChangeTabContents, but I
+  //             am striving for parity now rather than cleanliness. This is
+  //             required to make features like Duplicate Tab, Undo Close Tab,
+  //             etc not result in sad tab.
+  new_contents->DidBecomeSelected();
+  if (BrowserList::GetLastActive() == browser_ &&
+      !browser_->tabstrip_model()->closing_all() && GetWindow()->IsVisible()) {
+    // We only restore focus if our window is visible, to avoid invoking blur
+    // handlers when we are eventually shown.
+    new_contents->view()->RestoreFocus();
+  }
+
+  // Update all the UI bits.
+  UpdateTitleBar();
+  UpdateToolbar(new_contents, true);
+  UpdateUIForContents(new_contents);
+}
+
 #if !defined(OS_CHROMEOS)
 // static
 BrowserWindow* BrowserWindow::CreateBrowserWindow(Browser* browser) {
diff --git a/chrome/browser/views/frame/browser_view.h b/chrome/browser/views/frame/browser_view.h
index 37657f0..d2cadda 100644
--- a/chrome/browser/views/frame/browser_view.h
+++ b/chrome/browser/views/frame/browser_view.h
@@ -24,6 +24,7 @@
 #include "chrome/browser/views/tabs/tab_strip.h"
 #include "chrome/browser/views/tabs/base_tab_strip.h"
 #include "chrome/browser/views/unhandled_keyboard_event_handler.h"
+#include "chrome/common/notification_registrar.h"
 #include "gfx/native_widget_types.h"
 #include "views/window/client_view.h"
 #include "views/window/window_delegate.h"
@@ -335,6 +336,10 @@ class BrowserView : public BrowserBubbleHost,
                              TabContents* new_contents,
                              int index,
                              bool user_gesture);
+  virtual void TabReplacedAt(TabContents* old_contents,
+                             TabContents* new_contents,
+                             int index,
+                             TabStripModelObserver::TabReplaceType type);
   virtual void TabStripEmpty();
 
   // Overridden from menus::SimpleMenuModel::Delegate:
@@ -412,6 +417,8 @@ class BrowserView : public BrowserBubbleHost,
  private:
   friend class BrowserViewLayout;
 
+  class ContentsContainer;
+
 #if defined(OS_WIN)
   // Creates the system menu.
   void InitSystemMenu();
@@ -477,8 +484,17 @@ class BrowserView : public BrowserBubbleHost,
   // Initialize the hung plugin detector.
   void InitHangMonitor();
 
-  // Initialize class statics.
-  static void InitClass();
+  // Shows the match preview for the selected tab contents.
+  void ShowMatchPreview();
+
+  // Hides the match preview for the selected tab contents.
+  void HideMatchPreview();
+
+  // Invoked from TabSelectedAt or when the match preview is made active.  Is
+  // |change_tab_contents| is true, |new_contents| is added to the view
+  // hierarchy, if |change_tab_contents| is false, it's assumed |new_contents|
+  // has already been added to the view hierarchy.
+  void ProcessTabSelected(TabContents* new_contents, bool change_tab_contents);
 
   // Last focused view that issued a tab traversal.
   int last_focused_view_storage_id_;
@@ -515,6 +531,12 @@ class BrowserView : public BrowserBubbleHost,
   // The view that contains devtools window for the selected TabContents.
   TabContentsContainer* devtools_container_;
 
+  // The view that contains the match preview TabContents.
+  TabContentsContainer* preview_container_;
+
+  // The view managing both the contents_container_ and preview_container_.
+  ContentsContainer* contents_;
+
   // Split view containing the contents container and devtools container.
   views::SingleSplitView* contents_split_;
 
@@ -576,6 +598,8 @@ class BrowserView : public BrowserBubbleHost,
 
   scoped_ptr<AccessibleViewHelper> accessible_view_helper_;
 
+  NotificationRegistrar registrar_;
+
   DISALLOW_COPY_AND_ASSIGN(BrowserView);
 };
 
diff --git a/chrome/browser/views/location_bar/location_bar_view.cc b/chrome/browser/views/location_bar/location_bar_view.cc
index f42d9af..e8d8e05 100644
--- a/chrome/browser/views/location_bar/location_bar_view.cc
+++ b/chrome/browser/views/location_bar/location_bar_view.cc
@@ -19,6 +19,7 @@
 #include "chrome/browser/extensions/extensions_service.h"
 #include "chrome/browser/profile.h"
 #include "chrome/browser/search_engines/template_url_model.h"
+#include "chrome/browser/tab_contents/match_preview.h"
 #include "chrome/browser/view_ids.h"
 #include "chrome/browser/views/browser_dialogs.h"
 #include "chrome/browser/views/location_bar/content_setting_image_view.h"
@@ -712,6 +713,13 @@ void LocationBarView::OnChanged() {
           location_entry_->GetIcon()));
   Layout();
   SchedulePaint();
+
+  if (MatchPreview::IsEnabled() && GetTabContents() &&
+      !profile_->IsOffTheRecord()) {
+    GURL url = location_entry_->model()->user_input_in_progress() ?
+        location_entry_->model()->CurrentURL() : GURL();
+    GetTabContents()->match_preview()->Update(url);
+  }
 }
 
 void LocationBarView::OnInputInProgress(bool in_progress) {
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index 375120e..7e9d7fe 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -2484,6 +2484,8 @@
         'browser/tab_contents/interstitial_page.h',
         'browser/tab_contents/language_state.h',
         'browser/tab_contents/language_state.cc',
+        'browser/tab_contents/match_preview.cc',
+        'browser/tab_contents/match_preview.h',
         'browser/tab_contents/navigation_controller.cc',
         'browser/tab_contents/navigation_controller.h',
         'browser/tab_contents/navigation_entry.cc',
@@ -2514,8 +2516,8 @@
         'browser/tab_contents/tab_contents_view_gtk.h',
         'browser/tab_contents/tab_contents_view_mac.h',
         'browser/tab_contents/tab_contents_view_mac.mm',
-        'browser/tab_contents/tab_specific_content_settings.h',
         'browser/tab_contents/tab_specific_content_settings.cc',
+        'browser/tab_contents/tab_specific_content_settings.h',
         'browser/tab_contents/tab_util.cc',
         'browser/tab_contents/tab_util.h',
         'browser/tab_contents/thumbnail_generator.cc',
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 27e5cf4..34b8be9 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -376,6 +376,9 @@ const char kEnableGPURendering[]            = "enable-gpu-rendering";
 // builds.
 const char kEnableLogging[]                 = "enable-logging";
 
+// Is match preview enabled?
+const char kEnableMatchPreview[]            = "enable-match-preview";
+
 // Allows reporting memory info (JS heap size) to page.
 const char kEnableMemoryInfo[]              = "enable-memory-info";
 
diff --git a/chrome/common/chrome_switches.h b/chrome/common/chrome_switches.h
index 362a3a6..fbc8b81 100644
--- a/chrome/common/chrome_switches.h
+++ b/chrome/common/chrome_switches.h
@@ -122,6 +122,7 @@ extern const char kEnableIndexedDatabase[];
 extern const char kEnableInMemoryURLIndex[];
 extern const char kEnableIPv6[];
 extern const char kEnableLogging[];
+extern const char kEnableMatchPreview[];
 extern const char kEnableMemoryInfo[];
 extern const char kEnableMonitorProfile[];
 extern const char kEnableNaCl[];
diff --git a/chrome/common/notification_type.h b/chrome/common/notification_type.h
index ed8b2b2..7c19c9e 100644
--- a/chrome/common/notification_type.h
+++ b/chrome/common/notification_type.h
@@ -393,6 +393,10 @@ class NotificationType {
     // pointer.
     RENDER_VIEW_HOST_CREATED_FOR_TAB,
 
+    // Sent when MatchPreview creates the preview TabContents. The source is the
+    // TabContents the MatchPreview is associated with.
+    MATCH_PREVIEW_TAB_CONTENTS_CREATED,
+
     // Stuff inside the tabs ---------------------------------------------------
 
     // This message is sent after a constrained window has been closed.  The