[filebrowser] Introduce View action for supported file types (e.g. pdf).

chrome/test/data/extensions/api_test/filesystem_handler_write/tab.js

 // 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.
 
 /*
 This extension is a file intent handler and does the following during the test:
 
 1. It first registers content hander.
 2. When content handler callback is invoked, opens tab.html page and passes
    file url via hash ref.
@@ skipping 75 matching lines @@
   reader.onerror = function(e) {
     errorCallback({message: "Unable to read file."});
   };
   entry.file(function(file) {
     reader.readAsText(file);
   },
   errorCallback);
 }
 
 function executeListener(id, details) {
-  if (id != "TextAction" && id != "BaseAction" && id != "JpegAction") {
+  if (id != "AbcAction" && id != "BaseAction" && id != "123Action") {
     chrome.test.fail("Unexpected action id: " + id);
     return;
   }
   var file_entries = details.entries;
   if (!file_entries || file_entries.length != 1) {
     chrome.test.fail("Unexpected file url list");
     return;
   }
   chrome.tabs.get(details.tab_id, function(tab) {
     if (tab.title != "file browser component test") {
       chrome.test.fail("Unexpected tab title: " + tab.title);
       return;
     }
     runFileSystemHandlerTest(file_entries);
   });
 }
 
 chrome.fileBrowserHandler.onExecute.addListener(executeListener);
 
 // This extension just initializes its chrome.fileBrowserHandler.onExecute
 // event listener, the real testing is done when this extension's handler is
 // invoked from filebrowser_component tests. This event will be raised from that
 // component extension test and it simulates user action in the file browser.
 // tab.html part of this extension can run only after the component raises this
 // event, since that operation sets the propery security context and creates
 // event's payload with proper file Entry instances. tab.html will return
 // results of its execution to filebrowser_component test through a
 // cross-component message.
 chrome.test.succeed();