Re-land alexbost's experimental offscreenTabs API.

chrome/browser/extensions/api/offscreen_tabs/offscreen_tabs_api.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/extensions/api/offscreen_tabs/offscreen_tabs_api.h"
+
+#include <algorithm>
+#include <vector>
+
+#include "base/hash_tables.h"
+#include "base/json/json_writer.h"
+#include "base/memory/linked_ptr.h"
+#include "base/memory/scoped_vector.h"
+#include "base/lazy_instance.h"
+#include "base/string_number_conversions.h"
+#include "base/string_util.h"
+#include "base/values.h"
+#include "chrome/browser/extensions/api/offscreen_tabs/offscreen_tabs_constants.h"
+#include "chrome/browser/extensions/extension_event_names.h"
+#include "chrome/browser/extensions/extension_event_router.h"
+#include "chrome/browser/extensions/extension_function_dispatcher.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/extensions/extension_tab_util.h"
+#include "chrome/browser/extensions/extension_tabs_module.h"
+#include "chrome/browser/extensions/extension_tabs_module_constants.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_window.h"
+#include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
+#include "chrome/browser/ui/window_sizer.h"
+#include "chrome/common/chrome_notification_types.h"
+#include "chrome/common/extensions/extension.h"
+#include "chrome/common/extensions/extension_error_utils.h"
+#include "chrome/common/extensions/extension_messages.h"
+#include "chrome/common/pref_names.h"
+#include "chrome/common/url_constants.h"
+#include "content/public/browser/navigation_controller.h"
+#include "content/public/browser/notification_details.h"
+#include "content/public/browser/notification_source.h"
+#include "content/public/browser/render_view_host.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_view.h"
+
+using content::NavigationController;
+using content::NotificationDetails;
+using content::NotificationSource;
+using content::WebContents;
+using WebKit::WebInputEvent;
+
+namespace keys = extensions::offscreen_tabs_constants;
+namespace tabs_keys = extension_tabs_module_constants;
+namespace events = extension_event_names;
+
+namespace {
+
+class ParentTab;
+
+// This class is responsible for the life cycle of an offscreen tab.
+class OffscreenTab : public content::NotificationObserver {
+ public:
+  OffscreenTab();
+  virtual ~OffscreenTab();
+  void Init(const GURL& url,
+            const int width,
+            const int height,
+            Profile* profile,
+            ParentTab* parent_tab);
+
+  TabContentsWrapper* tab_contents() const {
+    return tab_contents_wrapper_.get();
+  }
+  WebContents* web_contents() const {
+    return tab_contents()->web_contents();
+  }
+  int GetID() const { return ExtensionTabUtil::GetTabId(web_contents()); }
+  ParentTab* parent_tab() { return parent_tab_; }
+
+  // Creates a representation of this OffscreenTab for use by the API methods.
+  // Passes ownership to the caller.
+  DictionaryValue* CreateValue() const;
+
+  // Navigates the tab to the |url|.
+  void NavigateToURL(const GURL& url) {
+    web_contents()->GetController().LoadURL(
+        url, content::Referrer(), content::PAGE_TRANSITION_LINK, std::string());
+  }
+
+  // Adjusts the tab's dimensions to the specified |width| and |height|.
+  void SetSize(int width, int height) {
+    // TODO(jstritar): this doesn't seem to work on ChromeOS.
+    web_contents()->GetView()->SizeContents(gfx::Size(width, height));
+  }
+
+ private:
+  virtual void Observe(int type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details) OVERRIDE;
+
+  content::NotificationRegistrar registrar_;
+  scoped_ptr<TabContentsWrapper> tab_contents_wrapper_;
+  ParentTab* parent_tab_;
+
+  DISALLOW_COPY_AND_ASSIGN(OffscreenTab);
+};
+
+typedef ScopedVector<OffscreenTab> OffscreenTabs;
+
+// Holds info about a tab that has spawned at least one offscreen tab.
+// Each ParentTab keeps track of its child offscreen tabs. The ParentTab is also
+// responsible for killing its children when it navigates away or gets closed.
+class ParentTab : public content::NotificationObserver {
+ public:
+  ParentTab();
+  virtual ~ParentTab();
+  void Init(WebContents* web_contents,
+            const std::string& extension_id);
+
+  TabContentsWrapper* tab_contents() { return tab_contents_wrapper_; }
+  int GetID() { return ExtensionTabUtil::GetTabId(web_contents()); }
+  WebContents* web_contents() {
+    return tab_contents()->web_contents();
+  }
+
+  // Returns the offscreen tabs spawned by this tab.
+  const OffscreenTabs& offscreen_tabs() { return offscreen_tabs_; }
+  const std::string& extension_id() const { return extension_id_; }
+
+  // Tab takes ownership of OffscreenTab.
+  void AddOffscreenTab(OffscreenTab *tab);
+
+  // Removes the offscreen |tab| and returns true if this parent has no more
+  // offscreen tabs.
+  bool RemoveOffscreenTab(OffscreenTab *tab);
+
+ private:
+  virtual void Observe(int type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details) OVERRIDE;
+
+  content::NotificationRegistrar registrar_;
+
+  TabContentsWrapper* tab_contents_wrapper_;
+  OffscreenTabs offscreen_tabs_;
+  std::string extension_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(ParentTab);
+};
+
+// This map keeps track of all tabs that are happy parents of offscreen tabs.
+class OffscreenTabMap {
+ public:
+  OffscreenTabMap();
+  ~OffscreenTabMap();
+
+  // Returns true if this map tracks |parent_tab|.
+  bool ContainsTab(ParentTab* parent_tab);
+
+  // Gets an offscreen tab by ID.
+  bool GetOffscreenTab(const int offscreen_tab_id,
+                       UIThreadExtensionFunction* function,
+                       OffscreenTab** offscreen_tab,
+                       std::string* error);
+
+  // Gets a parent tab from its contents for the given extension id.
+  // Returns NULL if no such tab exists.
+  ParentTab* GetParentTab(WebContents* parent_contents,
+                          const std::string& extension_id);
+
+  // Creates a new offscreen tab and a mapping between the |parent_tab| and
+  // the offscreen tab. Takes ownership of |parent_tab|, if it does not already
+  // have a mapping for it.
+  const OffscreenTab& CreateOffscreenTab(ParentTab* parent_tab,
+                                         const GURL& url,
+                                         const int width,
+                                         const int height,
+                                         const std::string& extension_id);
+
+  // Removes the mapping between a parent tab and an offscreen tab.
+  // May cause the OffscreenTab object associated with the parent to be deleted.
+  bool RemoveOffscreenTab(const int offscreen_tab_id,
+                          UIThreadExtensionFunction* function,
+                          std::string* error);
+
+  // Removes and deletes |parent_tab| and all it's offscreen tabs.
+  void RemoveParentTab(ParentTab* parent_tab);
+
+ private:
+  typedef base::hash_map<int, linked_ptr<ParentTab> > TabMap;
+  TabMap map_;
+
+  DISALLOW_COPY_AND_ASSIGN(OffscreenTabMap);
+};
+
+static base::LazyInstance<OffscreenTabMap> g_offscreen_tab_map =
+    LAZY_INSTANCE_INITIALIZER;
+
+// Gets the map of parent tabs to offscreen tabs.
+OffscreenTabMap* GetMap() {
+  return &g_offscreen_tab_map.Get();
+}
+
+// Gets the WebContents of the tab that instantiated the extension API call.
+// Returns NULL if there was an error.
+// Note that you can't create offscreen tabs from background pages, since they
+// don't have an associated WebContents. The lifetime of offscreen tabs is tied
+// to their creating tab, so requiring visible tabs as the parent helps prevent
+// offscreen tab leaking.
+WebContents* GetCurrentWebContents(UIThreadExtensionFunction* function,
+                                   std::string* error) {
+  WebContents* web_contents =
+      function->dispatcher()->delegate()->GetAssociatedWebContents();
+  if (web_contents)
+    return web_contents;
+
+  *error = keys::kCurrentTabNotFound;
+  return NULL;
+}
+
+OffscreenTab::OffscreenTab() : parent_tab_(NULL) {}
+OffscreenTab::~OffscreenTab() {}
+
+void OffscreenTab::Init(const GURL& url,
+                        const int width,
+                        const int height,
+                        Profile* profile,
+                        ParentTab* parent_tab) {
+  // Create the offscreen tab.
+  WebContents* web_contents = WebContents::Create(
+      profile, NULL, MSG_ROUTING_NONE, NULL, NULL);
+  tab_contents_wrapper_.reset(new TabContentsWrapper(web_contents));
+
+  // Setting the size starts the renderer.
+  SetSize(width, height);
+  NavigateToURL(url);
+
+  parent_tab_ = parent_tab;
+
+  // Register for tab notifications.
+  registrar_.Add(
+      this,
+      content::NOTIFICATION_NAV_ENTRY_COMMITTED,
+      content::Source<NavigationController>(&(web_contents->GetController())));
+}
+
+DictionaryValue* OffscreenTab::CreateValue() const {
+  DictionaryValue* result = new DictionaryValue();
+  result->SetInteger(
+      tabs_keys::kIdKey, ExtensionTabUtil::GetTabId(web_contents()));
+  result->SetString(tabs_keys::kUrlKey, web_contents()->GetURL().spec());
+  result->SetInteger(tabs_keys::kWidthKey,
+      web_contents()->GetView()->GetContainerSize().width());
+  result->SetInteger(tabs_keys::kHeightKey,
+      web_contents()->GetView()->GetContainerSize().height());
+  return result;
+}
+
+void OffscreenTab::Observe(int type,
+                           const NotificationSource& source,
+                           const NotificationDetails& details) {
+  CHECK_EQ(content::NOTIFICATION_NAV_ENTRY_COMMITTED, type);
+
+  DictionaryValue* changed_properties = new DictionaryValue();
+  changed_properties->SetString(
+      tabs_keys::kUrlKey, web_contents()->GetURL().spec());
+
+  ListValue args;
+  args.Append(Value::CreateIntegerValue(
+      ExtensionTabUtil::GetTabId(web_contents())));
+  args.Append(changed_properties);
+  args.Append(CreateValue());
+  std::string json_args;
+  base::JSONWriter::Write(&args, &json_args);
+
+  // The event router only dispatches the event to renderers listening for the
+  // event.
+  Profile* profile = parent_tab_->tab_contents()->profile();
+  profile->GetExtensionEventRouter()->DispatchEventToRenderers(
+      events::kOnOffscreenTabUpdated, json_args, profile, GURL());
+}
+
+ParentTab::ParentTab() : tab_contents_wrapper_(NULL) {}
+ParentTab::~ParentTab() {}
+
+void ParentTab::Init(WebContents* web_contents,
+                     const std::string& extension_id) {
+  CHECK(web_contents);
+
+  extension_id_ = extension_id;
+  tab_contents_wrapper_ =
+      TabContentsWrapper::GetCurrentWrapperForContents(web_contents);
+
+  CHECK(tab_contents_wrapper_);
+
+  // Register for tab notifications.
+  registrar_.Add(
+      this,
+      content::NOTIFICATION_NAV_ENTRY_COMMITTED,
+      content::Source<NavigationController>(&(web_contents->GetController())));
+  registrar_.Add(
+      this,
+      content::NOTIFICATION_WEB_CONTENTS_DESTROYED,
+      content::Source<WebContents>(web_contents));
+}
+
+void ParentTab::AddOffscreenTab(OffscreenTab *offscreen_tab) {
+  offscreen_tabs_.push_back(offscreen_tab);
+}
+
+bool ParentTab::RemoveOffscreenTab(OffscreenTab *offscreen_tab) {
+  OffscreenTabs::iterator it_tab = std::find(
+      offscreen_tabs_.begin(), offscreen_tabs_.end(), offscreen_tab);
+  offscreen_tabs_.erase(it_tab);
+  return offscreen_tabs_.empty();
+}
+
+void ParentTab::Observe(int type,
+                        const NotificationSource& source,
+                        const NotificationDetails& details) {
+  CHECK(type == content::NOTIFICATION_NAV_ENTRY_COMMITTED ||
+        type == content::NOTIFICATION_WEB_CONTENTS_DESTROYED);
+  GetMap()->RemoveParentTab(this);
+}
+
+OffscreenTabMap::OffscreenTabMap() {}
+OffscreenTabMap::~OffscreenTabMap() {}
+
+bool OffscreenTabMap::ContainsTab(ParentTab* parent_tab) {
+  return map_.find(parent_tab->GetID()) != map_.end();
+}
+
+bool OffscreenTabMap::GetOffscreenTab(const int offscreen_tab_id,
+                                      UIThreadExtensionFunction* function,
+                                      OffscreenTab** offscreen_tab,
+                                      std::string* error) {
+  // Ensure that the current tab is the parent of the offscreen tab.
+  WebContents* web_contents = GetCurrentWebContents(function, error);
+  if (!web_contents)
+    return false;
+
+  ParentTab* parent_tab = GetMap()->GetParentTab(
+      web_contents, function->extension_id());
+  if (parent_tab) {
+    const OffscreenTabs& tabs = parent_tab->offscreen_tabs();
+    for (OffscreenTabs::const_iterator i = tabs.begin(); i != tabs.end(); ++i) {
+      if ((*i)->GetID() == offscreen_tab_id) {
+        *offscreen_tab = *i;
+        return true;
+      }
+    }
+  }
+
+  *error = ExtensionErrorUtils::FormatErrorMessage(
+      keys::kOffscreenTabNotFoundError, base::IntToString(offscreen_tab_id));
+  return false;
+}
+
+ParentTab* OffscreenTabMap::GetParentTab(WebContents* parent_contents,
+                                         const std::string& extension_id) {
+  CHECK(parent_contents);
+
+  int parent_tab_id = ExtensionTabUtil::GetTabId(parent_contents);
+  if (map_.find(parent_tab_id) == map_.end())
+    return NULL;
+
+  return map_[parent_tab_id].get();
+}
+
+const OffscreenTab& OffscreenTabMap::CreateOffscreenTab(
+    ParentTab* parent_tab,
+    const GURL& url,
+    const int width,
+    const int height,
+    const std::string& ext_id) {
+  CHECK(parent_tab);
+
+  // Assume ownership of |parent_tab| if we haven't already.
+  if (!ContainsTab(parent_tab)) {
+    map_[ExtensionTabUtil::GetTabId(parent_tab->web_contents())].reset(
+        parent_tab);
+  }
+
+  OffscreenTab* offscreen_tab = new OffscreenTab();
+  offscreen_tab->Init(
+      url, width, height, parent_tab->tab_contents()->profile(), parent_tab);
+  parent_tab->AddOffscreenTab(offscreen_tab);
+
+  return *offscreen_tab;
+}
+
+bool OffscreenTabMap::RemoveOffscreenTab(
+    const int offscreen_tab_id,
+    UIThreadExtensionFunction* function,
+    std::string* error) {
+  OffscreenTab* offscreen_tab = NULL;
+  if (!GetOffscreenTab(offscreen_tab_id, function, &offscreen_tab, error))
+    return false;
+
+  // Tell the parent tab to remove the offscreen tab, and then remove the
+  // parent tab if there are no more children.
+  ParentTab* parent_tab = offscreen_tab->parent_tab();
+  if (parent_tab->RemoveOffscreenTab(offscreen_tab))
+    RemoveParentTab(parent_tab);
+
+  return true;
+}
+
+void OffscreenTabMap::RemoveParentTab(ParentTab* parent_tab) {
+  CHECK(parent_tab);
+  CHECK(ContainsTab(parent_tab));
+
+  map_.erase(parent_tab->GetID());
+}
+
+bool CopyModifiers(const DictionaryValue* js_event,
+                   WebInputEvent* event) {
+  bool alt_key = false;
+  if (js_event->HasKey(keys::kEventAltKeyKey)) {
+    if (!js_event->GetBoolean(keys::kEventAltKeyKey, &alt_key))
+      return false;
+  }
+  if (alt_key)
+    event->modifiers |= WebInputEvent::AltKey;
+
+  bool ctrl_key = false;
+  if (js_event->HasKey(keys::kEventCtrlKeyKey)) {
+    if (!js_event->GetBoolean(keys::kEventCtrlKeyKey, &ctrl_key))
+      return false;
+  }
+  if (ctrl_key)
+    event->modifiers |= WebInputEvent::ControlKey;
+
+  bool meta_key = false;
+  if (js_event->HasKey(keys::kEventMetaKeyKey)) {
+    if (!js_event->GetBoolean(keys::kEventMetaKeyKey, &meta_key))
+      return false;
+  }
+  if (meta_key)
+    event->modifiers |= WebInputEvent::MetaKey;
+
+  bool shift_key;
+  if (js_event->HasKey(keys::kEventShiftKeyKey)) {
+    if (!js_event->GetBoolean(keys::kEventShiftKeyKey, &shift_key))
+      return false;
+  }
+  if (shift_key)
+    event->modifiers |= WebInputEvent::ShiftKey;
+  return true;
+}
+
+}  // namespace
+
+CreateOffscreenTabFunction::CreateOffscreenTabFunction() {}
+CreateOffscreenTabFunction::~CreateOffscreenTabFunction() {}
+
+bool CreateOffscreenTabFunction::RunImpl() {
+  DictionaryValue* create_props;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetDictionary(0, &create_props));
+
+  std::string url_string;
+  EXTENSION_FUNCTION_VALIDATE(create_props->GetString(
+      tabs_keys::kUrlKey, &url_string));
+
+  GURL url = ExtensionTabUtil::ResolvePossiblyRelativeURL(
+      url_string, GetExtension());
+  if (!url.is_valid()) {
+    error_ = ExtensionErrorUtils::FormatErrorMessage(
+        tabs_keys::kInvalidUrlError, url_string);
+    return false;
+  }
+
+  if (ExtensionTabUtil::IsCrashURL(url)) {
+    error_ = tabs_keys::kNoCrashBrowserError;
+    return false;
+  }
+
+  gfx::Rect window_bounds;
+  Browser* browser = GetCurrentBrowser();
+  if (!browser) {
+    error_ = tabs_keys::kNoCurrentWindowError;
+    return false;
+  }
+
+  WindowSizer::GetBrowserWindowBounds(
+      std::string(), gfx::Rect(), browser, &window_bounds);
+
+  int width = window_bounds.width();
+  if (create_props->HasKey(tabs_keys::kWidthKey))
+    EXTENSION_FUNCTION_VALIDATE(
+        create_props->GetInteger(tabs_keys::kWidthKey, &width));
+
+  int height = window_bounds.height();
+  if (create_props->HasKey(tabs_keys::kHeightKey))
+    EXTENSION_FUNCTION_VALIDATE(
+        create_props->GetInteger(tabs_keys::kHeightKey, &height));
+
+
+  // Add the offscreen tab to the map so we don't lose track of it.
+  WebContents* web_contents = GetCurrentWebContents(this, &error_);
+  if (!web_contents)
+    return false;
+
+  ParentTab* parent_tab = GetMap()->GetParentTab(web_contents, extension_id());
+  if (!parent_tab) {
+    // Ownership is passed to the OffscreenMap in CreateOffscreenTab.
+    parent_tab = new ParentTab();
+    parent_tab->Init(web_contents, extension_id());
+  }
+
+  const OffscreenTab& offscreen_tab = GetMap()->CreateOffscreenTab(
+      parent_tab, url, width, height, extension_id());
+
+  // TODO(alexbost): Maybe the callback is called too soon. It should probably
+  // be called once we have navigated to the url.
+  if (has_callback()) {
+    result_.reset(offscreen_tab.CreateValue());
+    SendResponse(true);
+  }
+
+  return true;
+}
+
+GetOffscreenTabFunction::GetOffscreenTabFunction() {}
+GetOffscreenTabFunction::~GetOffscreenTabFunction() {}
+
+bool GetOffscreenTabFunction::RunImpl() {
+  int offscreen_tab_id;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(0, &offscreen_tab_id));
+
+  OffscreenTab* offscreen_tab = NULL;
+  if (!GetMap()->GetOffscreenTab(
+          offscreen_tab_id, this, &offscreen_tab, &error_)) {
+    error_ = ExtensionErrorUtils::FormatErrorMessage(
+        keys::kOffscreenTabNotFoundError, base::IntToString(offscreen_tab_id));
+    return false;
+  }
+
+  result_.reset(offscreen_tab->CreateValue());
+  return true;
+}
+
+GetAllOffscreenTabFunction::GetAllOffscreenTabFunction() {}
+GetAllOffscreenTabFunction::~GetAllOffscreenTabFunction() {}
+
+bool GetAllOffscreenTabFunction::RunImpl() {
+  WebContents* web_contents = GetCurrentWebContents(this, &error_);
+  if (!web_contents)
+    return NULL;
+
+  ParentTab* parent_tab = GetMap()->GetParentTab(web_contents, extension_id());
+  ListValue* tab_list = new ListValue();
+  if (parent_tab) {
+    for (OffscreenTabs::const_iterator i = parent_tab->offscreen_tabs().begin();
+         i != parent_tab->offscreen_tabs().end(); ++i)
+      tab_list->Append((*i)->CreateValue());
+  }
+
+  result_.reset(tab_list);
+  return true;
+}
+
+RemoveOffscreenTabFunction::RemoveOffscreenTabFunction() {}
+RemoveOffscreenTabFunction::~RemoveOffscreenTabFunction() {}
+
+bool RemoveOffscreenTabFunction::RunImpl() {
+  int offscreen_tab_id;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(0, &offscreen_tab_id));
+
+  OffscreenTab* offscreen_tab = NULL;
+  if (!GetMap()->GetOffscreenTab(
+          offscreen_tab_id, this, &offscreen_tab, &error_))
+    return false;
+
+  if (!GetMap()->RemoveOffscreenTab(offscreen_tab_id, this, &error_))
+    return false;
+
+  return true;
+}
+
+SendKeyboardEventOffscreenTabFunction::
+    SendKeyboardEventOffscreenTabFunction() {}
+SendKeyboardEventOffscreenTabFunction::
+    ~SendKeyboardEventOffscreenTabFunction() {}
+
+bool SendKeyboardEventOffscreenTabFunction::RunImpl() {
+  int offscreen_tab_id;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(0, &offscreen_tab_id));
+
+  OffscreenTab* offscreen_tab = NULL;
+  if (!GetMap()->GetOffscreenTab(
+          offscreen_tab_id, this, &offscreen_tab, &error_))
+    return false;
+
+  // JavaScript KeyboardEvent.
+  DictionaryValue* js_keyboard_event = NULL;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetDictionary(1, &js_keyboard_event));
+
+  NativeWebKeyboardEvent keyboard_event;
+
+  std::string type;
+  if (js_keyboard_event->HasKey(keys::kEventTypeKey)) {
+    EXTENSION_FUNCTION_VALIDATE(
+        js_keyboard_event->GetString(keys::kEventTypeKey, &type));
+  } else {
+    error_ = keys::kInvalidKeyboardEventObjectError;
+    return false;
+  }
+
+  if (type.compare(keys::kKeyboardEventTypeValueKeypress) == 0) {
+    keyboard_event.type = WebInputEvent::Char;
+  } else if (type.compare(keys::kKeyboardEventTypeValueKeydown) == 0) {
+    keyboard_event.type = WebInputEvent::KeyDown;
+  } else if (type.compare(keys::kKeyboardEventTypeValueKeyup) == 0) {
+    keyboard_event.type = WebInputEvent::KeyUp;
+  } else {
+    error_ = keys::kInvalidKeyboardEventObjectError;
+    return false;
+  }
+
+  int key_code;
+  if (js_keyboard_event->HasKey(keys::kKeyboardEventKeyCodeKey)) {
+    EXTENSION_FUNCTION_VALIDATE(js_keyboard_event->
+        GetInteger(keys::kKeyboardEventKeyCodeKey, &key_code));
+    keyboard_event.nativeKeyCode = key_code;
+    keyboard_event.windowsKeyCode = key_code;
+    keyboard_event.setKeyIdentifierFromWindowsKeyCode();
+  }
+
+  // Keypress = type character
+  if (type.compare(keys::kKeyboardEventTypeValueKeypress) == 0) {
+    int char_code;
+    if (js_keyboard_event->HasKey(keys::kKeyboardEventCharCodeKey)) {
+      EXTENSION_FUNCTION_VALIDATE(js_keyboard_event->
+          GetInteger(keys::kKeyboardEventCharCodeKey, &char_code));
+      keyboard_event.text[0] = char_code;
+      keyboard_event.unmodifiedText[0] = char_code;
+    } else {
+      error_ = keys::kInvalidKeyboardEventObjectError;
+      return false;
+    }
+  }
+
+  EXTENSION_FUNCTION_VALIDATE(
+      CopyModifiers(js_keyboard_event, &keyboard_event));
+
+  // Forward the event.
+  offscreen_tab->web_contents()->GetRenderViewHost()->
+      ForwardKeyboardEvent(keyboard_event);
+
+  return true;
+}
+
+SendMouseEventOffscreenTabFunction::SendMouseEventOffscreenTabFunction() {}
+SendMouseEventOffscreenTabFunction::~SendMouseEventOffscreenTabFunction() {}
+
+bool SendMouseEventOffscreenTabFunction::RunImpl() {
+  int offscreen_tab_id;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(0, &offscreen_tab_id));
+
+  OffscreenTab* offscreen_tab = NULL;
+  if (!GetMap()->GetOffscreenTab(
+          offscreen_tab_id, this, &offscreen_tab, &error_))
+    return false;
+
+  // JavaScript MouseEvent.
+  DictionaryValue* js_mouse_event = NULL;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetDictionary(1, &js_mouse_event));
+
+  std::string type;
+  if (js_mouse_event->HasKey(keys::kEventTypeKey)) {
+    EXTENSION_FUNCTION_VALIDATE(
+        js_mouse_event->GetString(keys::kEventTypeKey, &type));
+  } else {
+    error_ = keys::kInvalidMouseEventObjectError;
+    return false;
+  }
+
+  if (type.compare(keys::kMouseEventTypeValueMousewheel) == 0) {
+    WebKit::WebMouseWheelEvent wheel_event;
+
+    wheel_event.type = WebInputEvent::MouseWheel;
+
+    if (js_mouse_event->HasKey(keys::kMouseEventWheelDeltaXKey) &&
+        js_mouse_event->HasKey(keys::kMouseEventWheelDeltaYKey)) {
+      int delta_x, delta_y;
+      EXTENSION_FUNCTION_VALIDATE(js_mouse_event->
+          GetInteger(keys::kMouseEventWheelDeltaXKey, &delta_x));
+      EXTENSION_FUNCTION_VALIDATE(js_mouse_event->
+          GetInteger(keys::kMouseEventWheelDeltaYKey, &delta_y));
+      wheel_event.deltaX = delta_x;
+      wheel_event.deltaY = delta_y;
+    } else {
+      error_ = keys::kInvalidMouseEventObjectError;
+      return false;
+    }
+
+    // Forward the event.
+    offscreen_tab->web_contents()->GetRenderViewHost()->
+        ForwardWheelEvent(wheel_event);
+  } else {
+    WebKit::WebMouseEvent mouse_event;
+
+    if (type.compare(keys::kMouseEventTypeValueMousedown) == 0 ||
+        type.compare(keys::kMouseEventTypeValueClick) == 0) {
+      mouse_event.type = WebInputEvent::MouseDown;
+    } else if (type.compare(keys::kMouseEventTypeValueMouseup) == 0) {
+      mouse_event.type = WebInputEvent::MouseUp;
+    } else if (type.compare(keys::kMouseEventTypeValueMousemove) == 0) {
+      mouse_event.type = WebInputEvent::MouseMove;
+    } else {
+      error_ = keys::kInvalidMouseEventObjectError;
+      return false;
+    }
+
+    int button;
+    if (js_mouse_event->HasKey(keys::kMouseEventButtonKey)) {
+      EXTENSION_FUNCTION_VALIDATE(
+          js_mouse_event->GetInteger(keys::kMouseEventButtonKey, &button));
+    } else {
+      error_ = keys::kInvalidMouseEventObjectError;
+      return false;
+    }
+
+    if (button == keys::kMouseEventButtonValueLeft) {
+      mouse_event.button = WebKit::WebMouseEvent::ButtonLeft;
+    } else if (button == keys::kMouseEventButtonValueMiddle) {
+      mouse_event.button = WebKit::WebMouseEvent::ButtonMiddle;
+    } else if (button == keys::kMouseEventButtonValueRight) {
+      mouse_event.button = WebKit::WebMouseEvent::ButtonRight;
+    } else {
+      error_ = keys::kInvalidMouseEventObjectError;
+      return false;
+    }
+
+    if (HasOptionalArgument(2) && HasOptionalArgument(3)) {
+      EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(2, &mouse_event.x));
+      EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(3, &mouse_event.y));
+    } else {
+      error_ = keys::kNoMouseCoordinatesError;
+      return false;
+    }
+
+    EXTENSION_FUNCTION_VALIDATE(CopyModifiers(js_mouse_event, &mouse_event));
+
+    mouse_event.clickCount = 1;
+
+    // Forward the event.
+    offscreen_tab->web_contents()->GetRenderViewHost()->
+        ForwardMouseEvent(mouse_event);
+
+    // If the event is a click,
+    // fire a mouseup event in addition to the mousedown.
+    if (type.compare(keys::kMouseEventTypeValueClick) == 0) {
+      mouse_event.type = WebInputEvent::MouseUp;
+      offscreen_tab->web_contents()->GetRenderViewHost()->
+          ForwardMouseEvent(mouse_event);
+    }
+  }
+
+  return true;
+}
+
+ToDataUrlOffscreenTabFunction::ToDataUrlOffscreenTabFunction() {}
+ToDataUrlOffscreenTabFunction::~ToDataUrlOffscreenTabFunction() {}
+
+bool ToDataUrlOffscreenTabFunction::GetTabToCapture(
+    WebContents** web_contents, TabContentsWrapper** wrapper) {
+  int offscreen_tab_id;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(0, &offscreen_tab_id));
+
+  // TODO(alexbost): We want to optimize this function in order to get more
+  // image updates on the browser side. One improvement would be to implement
+  // another hash map in order to get offscreen tabs in O(1).
+  OffscreenTab* offscreen_tab = NULL;
+  if (!GetMap()->GetOffscreenTab(
+          offscreen_tab_id, this, &offscreen_tab, &error_))
+    return false;
+
+  *web_contents = offscreen_tab->web_contents();
+  *wrapper = offscreen_tab->tab_contents();
+  return true;
+}
+
+UpdateOffscreenTabFunction::UpdateOffscreenTabFunction() {}
+UpdateOffscreenTabFunction::~UpdateOffscreenTabFunction() {}
+
+bool UpdateOffscreenTabFunction::RunImpl() {
+  int offscreen_tab_id;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(0, &offscreen_tab_id));
+
+  OffscreenTab* offscreen_tab = NULL;
+  if (!GetMap()->GetOffscreenTab(
+          offscreen_tab_id, this, &offscreen_tab, &error_))
+    return false;
+
+  DictionaryValue* update_props;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetDictionary(1, &update_props));
+
+  web_contents_ = offscreen_tab->web_contents();
+  bool is_async = false;
+  if (!UpdateURLIfPresent(update_props, &is_async))
+    return false;
+
+  // Update the width and height, if specified.
+  if (update_props->HasKey(tabs_keys::kWidthKey) ||
+      update_props->HasKey(tabs_keys::kHeightKey)) {
+    int width;
+    if (update_props->HasKey(tabs_keys::kWidthKey))
+      EXTENSION_FUNCTION_VALIDATE(
+          update_props->GetInteger(tabs_keys::kWidthKey, &width));
+    else
+      web_contents_->GetView()->GetContainerSize().width();
+
+    int height;
+    if (update_props->HasKey(tabs_keys::kHeightKey))
+      EXTENSION_FUNCTION_VALIDATE(
+          update_props->GetInteger(tabs_keys::kHeightKey, &height));
+    else
+      web_contents_->GetView()->GetContainerSize().height();
+
+    offscreen_tab->SetSize(width, height);
+  }
+
+  // The response is sent from UpdateTabFunction::OnExecuteCodeFinish in the
+  // async case (when a "javascript": URL is sent to a tab).
+  if (!is_async)
+    SendResponse(true);
+
+  return true;
+}
+
+void UpdateOffscreenTabFunction::PopulateResult() {
+  // There's no result associated with this callback.
+}