Added new fileBrowserPrivate and fileHandler extension APIs

chrome/browser/extensions/extension_file_browser_private_api.cc

 // Copyright (c) 2011 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/extension_file_browser_private_api.h"
 
+#include "base/base64.h"
+#include "base/command_line.h"
 #include "base/json/json_writer.h"
 #include "base/logging.h"
+#include "base/memory/singleton.h"
+#include "base/stringprintf.h"
+#include "base/string_util.h"
 #include "base/task.h"
 #include "base/values.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/extensions/extension_event_router.h"
+#include "chrome/browser/extensions/extension_function_dispatcher.h"
+#include "chrome/browser/extensions/extension_process_manager.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/ui/webui/extension_icon_source.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/extension.h"
+#include "chrome/common/extensions/file_browser_handler.h"
 #include "content/browser/browser_thread.h"
+#include "content/browser/child_process_security_policy.h"
+#include "content/browser/renderer_host/render_process_host.h"
+#include "content/browser/renderer_host/render_view_host.h"
 #include "content/browser/tab_contents/tab_contents.h"
 #include "googleurl/src/gurl.h"
 #include "grit/generated_resources.h"
 #include "webkit/fileapi/file_system_context.h"
+#include "webkit/fileapi/file_system_mount_point_provider.h"
 #include "webkit/fileapi/file_system_operation.h"
+#include "webkit/fileapi/file_system_operation_context.h"
 #include "webkit/fileapi/file_system_path_manager.h"
 #include "webkit/fileapi/file_system_types.h"
+#include "webkit/fileapi/file_system_util.h"
+#include "webkit/fileapi/file_system_file_util.h"
+#include "webkit/fileapi/local_file_system_file_util.h"
 #include "ui/base/l10n/l10n_util.h"
 
+// Error messages.
+const char kFileError[] = "File error %d";
+const char kInvalidFileUrl[] = "Invalid file URL";
+
+const int kReadOnlyFilePermissions = base::PLATFORM_FILE_OPEN |
+                                     base::PLATFORM_FILE_READ |
+                                     base::PLATFORM_FILE_EXCLUSIVE_READ |
+                                     base::PLATFORM_FILE_ASYNC;
+
+const int kReadWriteFilePermissions = base::PLATFORM_FILE_OPEN |
+                                      base::PLATFORM_FILE_CREATE |
+                                      base::PLATFORM_FILE_OPEN_ALWAYS |
+                                      base::PLATFORM_FILE_CREATE_ALWAYS |
+                                      base::PLATFORM_FILE_READ |
+                                      base::PLATFORM_FILE_WRITE |
+                                      base::PLATFORM_FILE_EXCLUSIVE_READ |
+                                      base::PLATFORM_FILE_EXCLUSIVE_WRITE |
+                                      base::PLATFORM_FILE_ASYNC |
+                                      base::PLATFORM_FILE_TRUNCATE |
+                                      base::PLATFORM_FILE_WRITE_ATTRIBUTES;
+
+typedef std::vector<
+    std::pair<std::string, const FileBrowserHandler* > >
+        NamedHandlerList;
+
+typedef std::vector<const FileBrowserHandler*> ActionList;
+
+bool GetFileBrowserHandlers(Profile* profile,
+                           const GURL& selected_file_url,
+                           ActionList* results) {
+  ExtensionService* service = profile->GetExtensionService();
+  if (!service)
+    return false;  // In unit-tests, we may not have an ExtensionService.
+
+  for (ExtensionList::const_iterator iter = service->extensions()->begin();
+       iter != service->extensions()->end();
+       ++iter) {
+    const Extension* extension = iter->get();
+    if (!extension->file_browser_handlers())
+      continue;
+
+    for (Extension::FileBrowserHandlerList::const_iterator action_iter =
+             extension->file_browser_handlers()->begin();
+        action_iter != extension->file_browser_handlers()->end();
+        ++action_iter) {
+      const FileBrowserHandler* action = action_iter->get();
+      if (!action->MatchesURL(selected_file_url))
+        continue;
+
+      results->push_back(action_iter->get());
+    }
+  }
+  return true;
+}
+
+// Given the list of selected files, returns array of context menu tasks
+// that are shared
+bool FindCommonTasks(Profile* profile,
+                     ListValue* files_list,
+                     NamedHandlerList* named_action_list) {
+  named_action_list->clear();
+  ActionList common_tasks;
+  for (size_t i = 0; i < files_list->GetSize(); ++i) {
+    std::string file_url;
+    if (!files_list->GetString(i, &file_url))
+      return false;
+
+    ActionList file_actions;
+    if (!GetFileBrowserHandlers(profile, GURL(file_url), &file_actions))
+      return false;
+    // If there is nothing to do for one file, the intersection of tasks for all
+    // files will be empty at the end.
+    if (!file_actions.size()) {
+      common_tasks.clear();
+      return true;
+    }
+    // For the very first file, just copy elements.
+    if (i == 0) {
+      common_tasks.insert(common_tasks.begin(),
+                          file_actions.begin(),
+                          file_actions.end());
+      std::sort(common_tasks.begin(), common_tasks.end());
+    } else if (common_tasks.size()) {
+      // For all additional files, find intersection between the accumulated
+      // and file specific set.
+      std::sort(file_actions.begin(), file_actions.end());
+      ActionList intersection(common_tasks.size());
+      ActionList::iterator intersection_end =
+          std::set_intersection(common_tasks.begin(),
+                                common_tasks.end(),
+                                file_actions.begin(),
+                                file_actions.end(),
+                                intersection.begin());
+      common_tasks.clear();
+      common_tasks.insert(common_tasks.begin(),
+                          intersection.begin(),
+                          intersection_end);
+      std::sort(common_tasks.begin(), common_tasks.end());
+    }
+  }
+
+  // At the end, sort the results by task title.
+  // TODO(zelidrag): Wire this with ICU to make this sort I18N happy.
+  for (ActionList::const_iterator iter = common_tasks.begin();
+       iter != common_tasks.end(); ++iter) {
+    named_action_list->push_back(
+        std::pair<std::string, const FileBrowserHandler* >(
+            (*iter)->title(), *iter));
+  }
+  std::sort(named_action_list->begin(), named_action_list->end());
+  return true;
+}
+
+// Breaks down task_id that is used between getFileTasks() and executeTask() on
+// its building blocks. task_id field the following structure:
+//     <task-type>:<extension-id>/<task-action-id>
+// Currently, the only supported task-type is of 'context'.
+bool CrackTaskIdentifier(const std::string& task_id,
+                         std::string* target_extension_id,
+                         std::string* action_id) {
+  std::vector<std::string> result;
+  int count = Tokenize(task_id, std::string("|"), &result);
+  if (count != 2)
+    return false;
+  *target_extension_id = result[0];
+  *action_id = result[1];
+  return true;
+}
+
+std::string MakeTaskID(const char* extension_id,
+                       const char*  action_id) {
+  return base::StringPrintf("%s|%s", extension_id, action_id);
+}
 
 class LocalFileSystemCallbackDispatcher
     : public fileapi::FileSystemCallbackDispatcher {
  public:
   explicit LocalFileSystemCallbackDispatcher(
-      RequestLocalFileSystemFunction* function) : function_(function) {
+      RequestLocalFileSystemFunction* function,
+      Profile* profile,
+      int child_id,
+      scoped_refptr<const Extension> extension)
+      : function_(function),
+        profile_(profile),
+        child_id_(child_id),
+        extension_(extension)  {
     DCHECK(function_);
   }
+
   // fileapi::FileSystemCallbackDispatcher overrides.
   virtual void DidSucceed() OVERRIDE {
     NOTREACHED();
   }
+
   virtual void DidReadMetadata(const base::PlatformFileInfo& info,
                                const FilePath& unused) OVERRIDE {
     NOTREACHED();
   }
+
   virtual void DidReadDirectory(
       const std::vector<base::FileUtilProxy::Entry>& entries,
       bool has_more) OVERRIDE {
     NOTREACHED();
   }
+
   virtual void DidWrite(int64 bytes, bool complete) OVERRIDE {
     NOTREACHED();
   }
+
   virtual void DidOpenFileSystem(const std::string& name,
-                                 const GURL& root) OVERRIDE {
+                                 const GURL& root_path) OVERRIDE {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+    // Set up file permission access.
+    if (!SetupFileSystemAccessPermissions()) {
+      DidFail(base::PLATFORM_FILE_ERROR_SECURITY);
+      return;
+    }
+
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE,
         NewRunnableMethod(function_,
             &RequestLocalFileSystemFunction::RespondSuccessOnUIThread,
             name,
-            root));
-  }
+            root_path));
+  }
+
   virtual void DidFail(base::PlatformFileError error_code) OVERRIDE {
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE,
         NewRunnableMethod(function_,
             &RequestLocalFileSystemFunction::RespondFailedOnUIThread,
             error_code));
   }
+
  private:
+
+  // Grants file system access permissions to file browser component.
+  bool SetupFileSystemAccessPermissions() {
+    if (!extension_.get())
+      return false;
+
+    // Make sure that only component extension can access the entire
+    // local file system.
+    if (extension_->location() != Extension::COMPONENT
+#ifndef NDEBUG
+      && !CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kExposePrivateExtensionApi)
+#endif
+        ) {
+      NOTREACHED() << "Private method access by non-component extension "
+                   << extension_->id();
+      return false;
+    }
+
+    fileapi::FileSystemPathManager* path_manager =
+        profile_->GetFileSystemContext()->path_manager();
+    fileapi::ExternalFileSystemMountPointProvider* provider =
+        path_manager->external_provider();
+    if (!provider)
+      return false;
+
+    // Grant full access to File API from this component extension.
+    provider->GrantFullAccessToExtension(extension_->id());
+
+    // Grant R/W file permissions to the renderer hosting component
+    // extension for all paths exposed by our local file system provider.
+    std::vector<FilePath> root_dirs = provider->GetRootDirectories();
+    for (std::vector<FilePath>::iterator iter = root_dirs.begin();
+         iter != root_dirs.end();
+         ++iter) {
+      ChildProcessSecurityPolicy::GetInstance()->GrantPermissionsForFile(
+          child_id_, *iter, kReadWriteFilePermissions);
+    }
+    return true;
+  }
+
   RequestLocalFileSystemFunction* function_;
+  Profile* profile_;
+  // Renderer process id.
+  int child_id_;
+  // Extension source URL.
+  scoped_refptr<const Extension> extension_;
   DISALLOW_COPY_AND_ASSIGN(LocalFileSystemCallbackDispatcher);
 };
 
-RequestLocalFileSystemFunction::RequestLocalFileSystemFunction() {
-}
-
-RequestLocalFileSystemFunction::~RequestLocalFileSystemFunction() {
+void RequestLocalFileSystemFunction::RequestOnFileThread(
+    const GURL& source_url) {
+  fileapi::FileSystemOperation* operation =
+      new fileapi::FileSystemOperation(
+          new LocalFileSystemCallbackDispatcher(
+              this,
+              profile(),
+              dispatcher()->render_view_host()->process()->id(),
+              GetExtension()),
+          BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE),
+          profile()->GetFileSystemContext(),
+          NULL);
+  GURL origin_url = source_url.GetOrigin();
+  operation->OpenFileSystem(origin_url, fileapi::kFileSystemTypeExternal,
+                            false);     // create
 }
 
 bool RequestLocalFileSystemFunction::RunImpl() {
-  fileapi::FileSystemOperation* operation =
-      new fileapi::FileSystemOperation(
-          new LocalFileSystemCallbackDispatcher(this),
-          BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE),
-          profile()->GetFileSystemContext(),
-          NULL);
-  GURL origin_url = source_url().GetOrigin();
-  operation->OpenFileSystem(origin_url, fileapi::kFileSystemTypeExternal,
-                            false);     // create
+  BrowserThread::PostTask(
+      BrowserThread::FILE, FROM_HERE,
+      NewRunnableMethod(this,
+          &RequestLocalFileSystemFunction::RequestOnFileThread,
+          source_url_));
   // Will finish asynchronously.
   return true;
 }
 
 void RequestLocalFileSystemFunction::RespondSuccessOnUIThread(
-    const std::string& name, const GURL& root) {
+    const std::string& name, const GURL& root_path) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   result_.reset(new DictionaryValue());
   DictionaryValue* dict = reinterpret_cast<DictionaryValue*>(result_.get());
   dict->SetString("name", name);
-  dict->SetString("path", root.spec());
+  dict->SetString("path", root_path.spec());
   dict->SetInteger("error", base::PLATFORM_FILE_OK);
   SendResponse(true);
 }
 
 void RequestLocalFileSystemFunction::RespondFailedOnUIThread(
     base::PlatformFileError error_code) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  result_.reset(new DictionaryValue());
-  DictionaryValue* dict = reinterpret_cast<DictionaryValue*>(result_.get());
-  dict->SetInteger("error", static_cast<int>(error_code));
+  error_ = base::StringPrintf(kFileError, static_cast<int>(error_code));
+  SendResponse(false);
+}
+
+bool GetFileTasksFileBrowserFunction::RunImpl() {
+  ListValue* files_list = NULL;
+  if (!args_->GetList(0, &files_list))
+    return false;
+
+  ListValue* result_list = new ListValue();
+  result_.reset(result_list);
+
+  NamedHandlerList common_tasks;
+  if (!FindCommonTasks(profile_, files_list, &common_tasks))
+    return false;
+
+  ExtensionService* service = profile_->GetExtensionService();
+  for (NamedHandlerList::iterator iter = common_tasks.begin();
+       iter != common_tasks.end();
+       ++iter) {
+    const std::string extension_id = iter->second->extension_id();
+    const Extension* extension = service->GetExtensionById(extension_id, false);
+    CHECK(extension);
+    DictionaryValue* task = new DictionaryValue();
+    task->SetString("taskId", MakeTaskID(extension_id.data(),
+                                         iter->second->id().data()));
+    task->SetString("title", iter->second->title());
+    // TODO(zelidrag): Figure out how to expose icon URL that task defined in
+    // manifest instead of the default extension icon.
+    GURL icon =
+        ExtensionIconSource::GetIconURL(extension,
+                                        Extension::EXTENSION_ICON_SMALLISH,
+                                        ExtensionIconSet::MATCH_BIGGER,
+                                        false);     // grayscale
+    task->SetString("iconUrl", icon.spec());
+    result_list->Append(task);
+  }
+
+  // TODO(zelidrag, serya): Add intent content tasks to result_list once we
+  // implement that API.
   SendResponse(true);
+  return true;
+}
+
+class ExecuteTasksFileSystemCallbackDispatcher
+    : public fileapi::FileSystemCallbackDispatcher {
+ public:
+  explicit ExecuteTasksFileSystemCallbackDispatcher(
+      ExecuteTasksFileBrowserFunction* function,
+      Profile* profile,
+      int child_id,
+      const GURL& source_url,
+      scoped_refptr<const Extension> extension,
+      const std::string task_id,
+      const std::vector<GURL>& file_urls)
+      : function_(function),
+        profile_(profile),
+        source_url_(source_url),
+        extension_(extension),
+        task_id_(task_id),
+        origin_file_urls_(file_urls) {
+    DCHECK(function_);
+  }
+
+  // fileapi::FileSystemCallbackDispatcher overrides.
+  virtual void DidSucceed() OVERRIDE {
+    NOTREACHED();
+  }
+
+  virtual void DidReadMetadata(const base::PlatformFileInfo& info,
+                               const FilePath& unused) OVERRIDE {
+    NOTREACHED();
+  }
+
+  virtual void DidReadDirectory(
+      const std::vector<base::FileUtilProxy::Entry>& entries,
+      bool has_more) OVERRIDE {
+    NOTREACHED();
+  }
+
+  virtual void DidWrite(int64 bytes, bool complete) OVERRIDE {
+    NOTREACHED();
+  }
+
+  virtual void DidOpenFileSystem(const std::string& file_system_name,
+                                 const GURL& file_system_root) OVERRIDE {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+    ExecuteTasksFileBrowserFunction::FileDefinitionList file_list;
+    for (std::vector<GURL>::iterator iter = origin_file_urls_.begin();
+         iter != origin_file_urls_.end();
+         ++iter) {
+      // Set up file permission access.
+      ExecuteTasksFileBrowserFunction::FileDefinition file;
+      if (!SetupFileAccessPermissions(*iter, &file.target_file_url,
+                                      &file.virtual_path, &file.is_directory)) {
+        continue;
+      }
+      file_list.push_back(file);
+    }
+    if (file_list.empty())
+      return;
+
+    BrowserThread::PostTask(
+        BrowserThread::UI, FROM_HERE,
+        NewRunnableMethod(function_,
+            &ExecuteTasksFileBrowserFunction::ExecuteFileActionsOnUIThread,
+            task_id_,
+            file_system_name,
+            file_system_root,
+            file_list));
+  }
+
+  virtual void DidFail(base::PlatformFileError error_code) OVERRIDE {
+    LOG(WARNING) << "Local file system cant be resolved";
+  }
+
+ private:
+  // Checks legitimacy of file url and grants file RO access permissions from
+  // handler (target) extension and its renderer process.
+  bool SetupFileAccessPermissions(const GURL& origin_file_url,
+     GURL* target_file_url, FilePath* file_path, bool* is_directory) {
+
+    if (!extension_.get())
+      return false;
+
+    GURL file_origin_url;
+    FilePath virtual_path;
+    fileapi::FileSystemType type;
+
+    if (!CrackFileSystemURL(origin_file_url, &file_origin_url, &type,
+                            &virtual_path)) {
+      return false;
+    }
+
+    if (type != fileapi::kFileSystemTypeExternal)
+      return false;
+
+    fileapi::FileSystemPathManager* path_manager =
+        profile_->GetFileSystemContext()->path_manager();
+    if (!path_manager->IsAccessAllowed(file_origin_url,
+                                       type,
+                                       virtual_path)) {
+      return false;
+    }
+
+    // Make sure this url really being used by the right caller extension.
+    if (source_url_.GetOrigin() != file_origin_url) {
+      DidFail(base::PLATFORM_FILE_ERROR_SECURITY);
+      return false;
+    }
+
+    FilePath root_path = path_manager->GetFileSystemRootPathOnFileThread(
+        file_origin_url,
+        fileapi::kFileSystemTypeExternal,
+        virtual_path,
+        false);     // create
+    FilePath final_file_path = root_path.Append(virtual_path);
+
+    // Check if this file system entry exists first.
+    base::PlatformFileInfo file_info;
+    FilePath platform_path;
+    fileapi::FileSystemOperationContext file_system_operation_context(
+        profile_->GetFileSystemContext(),
+        fileapi::LocalFileSystemFileUtil::GetInstance());
+    if (base::PLATFORM_FILE_OK !=
+            fileapi::FileSystemFileUtil::GetInstance()->GetFileInfo(
+                &file_system_operation_context, final_file_path, &file_info,
+                &platform_path)) {
+      return false;
+    }
+
+    // TODO(zelidrag): Let's just prevent all symlinks for now. We don't want a
+    // USB drive content to point to something in the rest of the file system.
+    // Ideally, we should permit symlinks within the boundary of the same
+    // virtual mount point.
+    if (file_info.is_symbolic_link)
+      return false;
+
+    // TODO(zelidrag): Add explicit R/W + R/O permissions for non-component
+    // extensions.
+
+    // Get task details.
+    std::string target_extension_id;
+    std::string action_id;
+    if (!CrackTaskIdentifier(task_id_, &target_extension_id,
+                             &action_id)) {
+      return false;
+    }
+
+    // Get target extension's process.
+    RenderProcessHost* target_host =
+        profile_->GetExtensionProcessManager()->GetExtensionProcess(
+            target_extension_id);
+    if (!target_host)
+      return false;
+
+    // Grant R/O access permission to non-component extension and R/W to
+    // component extensions.
+    ChildProcessSecurityPolicy::GetInstance()->GrantPermissionsForFile(
+        target_host->id(), final_file_path,
+        extension_->location() != Extension::COMPONENT ?
+            kReadOnlyFilePermissions : kReadWriteFilePermissions);
+
+    // Grant access to this particular file to target extension. This will
+    // ensure that the target extension can access only this FS entry and
+    // prevent from traversing FS hierarchy upward.
+    fileapi::ExternalFileSystemMountPointProvider* external_provider =
+        path_manager->external_provider();
+    if (!external_provider)
+      return false;
+    external_provider->GrantFileAccessToExtension(target_extension_id,
+                                                  virtual_path);
+
+    // Output values.
+    GURL target_origin_url(Extension::GetBaseURLFromExtensionId(
+        target_extension_id));
+    GURL base_url = fileapi::GetFileSystemRootURI(target_origin_url,
+        fileapi::kFileSystemTypeExternal);
+    *target_file_url = GURL(base_url.spec() + virtual_path.value());
+    *file_path = virtual_path;
+    *is_directory = file_info.is_directory;
+    return true;
+  }
+
+  ExecuteTasksFileBrowserFunction* function_;
+  Profile* profile_;
+  // Extension source URL.
+  GURL source_url_;
+  scoped_refptr<const Extension> extension_;
+  std::string task_id_;
+  std::vector<GURL> origin_file_urls_;
+  DISALLOW_COPY_AND_ASSIGN(ExecuteTasksFileSystemCallbackDispatcher);
+};
+
+bool ExecuteTasksFileBrowserFunction::RunImpl() {
+  // First param is task id that was to the extension with getFileTasks call.
+  std::string task_id;
+  if (!args_->GetString(0, &task_id) || !task_id.size())
+    return false;
+
+  // The second param is the list of files that need to be executed with this
+  // task.
+  ListValue* files_list = NULL;
+  if (!args_->GetList(1, &files_list))
+    return false;
+
+  if (!files_list->GetSize())
+    return true;
+
+  InitiateFileTaskExecution(task_id, files_list);
+  SendResponse(true);
+  return true;
+}
+
+bool ExecuteTasksFileBrowserFunction::InitiateFileTaskExecution(
+    const std::string& task_id, ListValue* files_list) {
+  std::vector<GURL> file_urls;
+  for (size_t i = 0; i < files_list->GetSize(); i++) {
+    std::string origin_file_url;
+    if (!files_list->GetString(i, &origin_file_url)) {
+      error_ = kInvalidFileUrl;
+      SendResponse(false);
+      return false;
+    }
+    file_urls.push_back(GURL(origin_file_url));
+  }
+  // Get local file system instance on file thread.
+  BrowserThread::PostTask(
+      BrowserThread::FILE, FROM_HERE,
+      NewRunnableMethod(this,
+          &ExecuteTasksFileBrowserFunction::RequestFileEntryOnFileThread,
+          source_url_,
+          task_id,
+          file_urls));
+  result_.reset(new FundamentalValue(true));
+  return true;
+}
+
+void ExecuteTasksFileBrowserFunction::RequestFileEntryOnFileThread(
+    const GURL& source_url, const std::string& task_id,
+    const std::vector<GURL>& file_urls) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  fileapi::FileSystemOperation* operation =
+      new fileapi::FileSystemOperation(
+          new ExecuteTasksFileSystemCallbackDispatcher(
+              this,
+              profile(),
+              dispatcher()->render_view_host()->process()->id(),
+              source_url,
+              GetExtension(),
+              task_id,
+              file_urls),
+          BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE),
+          profile()->GetFileSystemContext(),
+          NULL);
+  GURL origin_url = source_url.GetOrigin();
+  operation->OpenFileSystem(origin_url, fileapi::kFileSystemTypeExternal,
+                            false);     // create
+}
+
+void ExecuteTasksFileBrowserFunction::ExecuteFileActionsOnUIThread(
+    const std::string& task_id,
+    const std::string& file_system_name,
+    const GURL& file_system_root,
+    const FileDefinitionList& file_list) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  ExtensionService* service = profile_->GetExtensionService();
+  if (!service)
+    return;
+  // Get task details.
+  std::string handler_extension_id;
+  std::string action_id;
+  if (!CrackTaskIdentifier(task_id, &handler_extension_id,
+                           &action_id)) {
+    LOG(WARNING) << "Invalid task " << task_id;
+    return;
+  }
+
+  const Extension* extension = service->GetExtensionById(handler_extension_id,
+                                                         false);
+  if (!extension)
+    return;
+
+  ExtensionEventRouter* event_router = profile_->GetExtensionEventRouter();
+  if (!event_router)
+    return;
+
+  scoped_ptr<ListValue> event_args(new ListValue());
+  ListValue* files_urls = new ListValue();
+  event_args->Append(Value::CreateStringValue(action_id));
+  event_args->Append(files_urls);
+  for (FileDefinitionList::const_iterator iter = file_list.begin();
+       iter != file_list.end();
+       ++iter) {
+    DictionaryValue* file_def = new DictionaryValue();
+    files_urls->Append(file_def);
+    file_def->SetString("fileSystemName", file_system_name);
+    file_def->SetString("fileSystemRoot", file_system_root.spec());
+    file_def->SetString("fileFullPath", iter->virtual_path.value());
+    file_def->SetBoolean("fileIsDirectory", iter->is_directory);
+  }
+  std::string json_args;
+  base::JSONWriter::Write(event_args.get(), false, &json_args);
+  std::string event_name = "contextMenus";
+  event_router->DispatchEventToExtension(
+      handler_extension_id, std::string("fileBrowserHandler.onExecute"),
+      json_args, profile_,
+      GURL());
 }
 
 FileDialogFunction::FileDialogFunction() {
 }
 
 FileDialogFunction::~FileDialogFunction() {
 }
 
 // static
 FileDialogFunction::Callback
@@ skipping 193 matching lines @@
   SET_STRING(IDS_FILE_BROWSER, COMPUTING_SELECTION);
   SET_STRING(IDS_FILE_BROWSER, NOTHING_SELECTED);
   SET_STRING(IDS_FILE_BROWSER, ONE_FILE_SELECTED);
   SET_STRING(IDS_FILE_BROWSER, MANY_FILES_SELECTED);
 
 #undef SET_STRING
 
   SendResponse(true);
   return true;
 }