Implemented drop hander for the Home toolbar button that accepts (only) links

chrome/browser/ui/views/home_button.cc

Index: chrome/browser/ui/views/home_button.cc
===================================================================
--- chrome/browser/ui/views/home_button.cc	(revision 0)
+++ chrome/browser/ui/views/home_button.cc	(revision 0)
@@ -0,0 +1,180 @@
+// 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/ui/views/home_button.h"
+
+#include "chrome/browser/prefs/pref_service.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/common/pref_names.h"
+#include "grit/generated_resources.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/views/bubble/bubble_delegate.h"
+#include "ui/views/controls/label.h"
+#include "ui/views/controls/link.h"
+#include "ui/views/controls/link_listener.h"
+#include "ui/views/layout/grid_layout.h"
+#include "ui/views/layout/layout_constants.h"
+#include "ui/views/widget/widget.h"
+
+// HomePageUndoBubble --------------------------------------------------------
+
+namespace {
+
+class HomePageUndoBubble : public views::BubbleDelegateView,
+                           public views::LinkListener {
+ public:
+  static void ShowBubble(Browser* browser,
+                         bool undo_value_is_ntp,
+                         const GURL& undo_url,
+                         views::View* anchor_view);
+  static void HideBubble();
+
+ private:
+  HomePageUndoBubble(Browser* browser, bool undo_value_is_ntp,
+                     const GURL& undo_url, views::View* anchor_view);
+  virtual ~HomePageUndoBubble();
+
+  // views::BubbleDelegateView:
+  virtual void Init() OVERRIDE;
+  virtual void WindowClosing() OVERRIDE;
+
+  // views::LinkListener:
+  virtual void LinkClicked(views::Link* source, int event_flags) OVERRIDE;
+
+  static HomePageUndoBubble* home_page_undo_bubble_;
+
+  Browser* browser_;
+  bool undo_value_is_ntp_;
+  GURL undo_url_;
+
+  DISALLOW_COPY_AND_ASSIGN(HomePageUndoBubble);
+};
+
+// static
+HomePageUndoBubble* HomePageUndoBubble::home_page_undo_bubble_ = NULL;
+
+void HomePageUndoBubble::ShowBubble(Browser* browser,
+                                    bool undo_value_is_ntp,
+                                    const GURL& undo_url,
+                                    views::View* anchor_view) {
+  HideBubble();
+  home_page_undo_bubble_ = new HomePageUndoBubble(browser,
+                                                  undo_value_is_ntp,
+                                                  undo_url,
+                                                  anchor_view);
+  views::BubbleDelegateView::CreateBubble(home_page_undo_bubble_);
+  home_page_undo_bubble_->StartFade(true);
+}
+
+void HomePageUndoBubble::HideBubble() {
+  if (home_page_undo_bubble_)
+    home_page_undo_bubble_->GetWidget()->Close();
+}
+
+HomePageUndoBubble::HomePageUndoBubble(
+    Browser* browser,
+    bool undo_value_is_ntp,
+    const GURL& undo_url,
+    views::View* anchor_view)
+    : BubbleDelegateView(anchor_view, views::BubbleBorder::TOP_LEFT),
+      browser_(browser),
+      undo_value_is_ntp_(undo_value_is_ntp),
+      undo_url_(undo_url) {
+}
+
+HomePageUndoBubble::~HomePageUndoBubble() {
+}
+
+void HomePageUndoBubble::Init() {
+  views::GridLayout* layout = new views::GridLayout(this);
+  SetLayoutManager(layout);
+
+  // Create two columns for the message and the undo link.
+  views::ColumnSet* cs = layout->AddColumnSet(0);
+  cs = layout->AddColumnSet(1);
+  cs->AddColumn(views::GridLayout::LEADING, views::GridLayout::BASELINE, 0,
+                views::GridLayout::USE_PREF, 0, 0);
+  cs->AddPaddingColumn(0, views::kRelatedControlHorizontalSpacing);
+  cs->AddColumn(views::GridLayout::CENTER, views::GridLayout::BASELINE, 0,
+                views::GridLayout::USE_PREF, 0, 0);
+
+  views::Label* message_label = new views::Label(
+      l10n_util::GetStringUTF16(IDS_TOOLBAR_INFORM_SET_HOME_PAGE));
+  message_label->SetHorizontalAlignment(gfx::ALIGN_LEFT);
+  layout->StartRow(0, 1);
+  layout->AddView(message_label);
+
+  views::Link* undo_link = new views::Link(
+      l10n_util::GetStringUTF16(IDS_ONE_CLICK_BUBBLE_UNDO));
+  undo_link->set_listener(this);
+  layout->AddView(undo_link);
+}
+
+void HomePageUndoBubble::LinkClicked(views::Link* source, int event_flags) {
+  PrefServiceBase* prefs =
+      PrefServiceBase::FromBrowserContext(browser_->profile());
+  prefs->SetBoolean(prefs::kHomePageIsNewTabPage, undo_value_is_ntp_);
+  prefs->SetString(prefs::kHomePage, undo_url_.spec());
+
+  HideBubble();
+}
+
+void HomePageUndoBubble::WindowClosing() {
+  // We have to reset |home_page_undo_bubble_| here, not in our destructor,
+  // because we'll be hidden first, then destroyed asynchronously.  If we wait
+  // to reset this, and the user triggers a call to ShowBubble() while the
+  // window is hidden but not destroyed, GetWidget()->Close() would be
+  // called twice.
+  DCHECK_EQ(this, home_page_undo_bubble_);
+  home_page_undo_bubble_ = NULL;
+}
+
+}  // namespace
+
+
+// HomeImageButton -----------------------------------------------------------
+
+HomeImageButton::HomeImageButton(
+    views::ButtonListener* listener,
+    Browser* browser)
+    : views::ImageButton(listener),
+      browser_(browser) {
+}
+
+HomeImageButton::~HomeImageButton() {
+}
+
+bool HomeImageButton::GetDropFormats(
+    int* formats,
+    std::set<OSExchangeData::CustomFormat>* custom_formats) {
+  *formats = ui::OSExchangeData::URL;
+  return true;
+}
+
+bool HomeImageButton::CanDrop(const OSExchangeData& data) {
+  return data.HasURL();
+}
+
+int HomeImageButton::OnDragUpdated(const ui::DropTargetEvent& event) {
+  return (event.source_operations() & ui::DragDropTypes::DRAG_LINK) ?
+      ui::DragDropTypes::DRAG_LINK : ui::DragDropTypes::DRAG_NONE;
+}
+
+int HomeImageButton::OnPerformDrop(const ui::DropTargetEvent& event) {
+  GURL new_homepage_url;
+  string16 title;
+  if (event.data().GetURLAndTitle(&new_homepage_url, &title) &&
+      new_homepage_url.is_valid()) {
+    PrefService* prefs = browser_->profile()->GetPrefs();
+    bool old_is_ntp = prefs->GetBoolean(prefs::kHomePageIsNewTabPage);
+    GURL old_homepage(prefs->GetString(prefs::kHomePage));
+
+    prefs->SetBoolean(prefs::kHomePageIsNewTabPage, false);
+    prefs->SetString(prefs::kHomePage, new_homepage_url.spec());
+
+    HomePageUndoBubble::ShowBubble(browser_, old_is_ntp, old_homepage, this);
+  }
+  return ui::DragDropTypes::DRAG_NONE;
+}