Make chrome.tabs.update's tabId parameter optional.

chrome/browser/extensions/extension_tabs_module.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_tabs_module.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/base64.h"
@@ skipping 874 matching lines @@
   if (contents)
     result_.reset(ExtensionTabUtil::CreateTabValue(contents));
 
   return true;
 }
 
 UpdateTabFunction::UpdateTabFunction() {
 }
 
 bool UpdateTabFunction::RunImpl() {
-  int tab_id;
-  EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(0, &tab_id));
   DictionaryValue* update_props;
   EXTENSION_FUNCTION_VALIDATE(args_->GetDictionary(1, &update_props));
 
+  Value* tab_value = NULL;
+  if (HasOptionalArgument(0)) {
+    EXTENSION_FUNCTION_VALIDATE(args_->Get(0, &tab_value));
+  }
+
+  int tab_id = -1;
+  TabContentsWrapper* contents = NULL;
+  if (tab_value == NULL || tab_value->IsType(Value::TYPE_NULL)) {
+    Browser* browser = GetCurrentBrowser();
+    if (!browser) {
+      error_ = keys::kNoCurrentWindowError;
+      return false;
+    }
+    contents = browser->tabstrip_model()->GetActiveTabContents();
+    if (!contents) {
+      error_ = keys::kNoSelectedTabError;
+      return false;
+    }
+    tab_id = ExtensionTabUtil::GetTabId(contents->tab_contents());
+  } else {
+    EXTENSION_FUNCTION_VALIDATE(tab_value->GetAsInteger(&tab_id));
+  }
+
+  int tab_index = -1;
   TabStripModel* tab_strip = NULL;
-  TabContentsWrapper* contents = NULL;
-  int tab_index = -1;
   if (!GetTabById(tab_id, profile(), include_incognito(),
-                  NULL, &tab_strip, &contents, &tab_index, &error_))
+                  NULL, &tab_strip, &contents, &tab_index, &error_)) {
     return false;
-
+  }
   NavigationController& controller = contents->controller();
 
   // TODO(rafaelw): handle setting remaining tab properties:
   // -title
   // -favIconUrl
 
   // Navigate the tab to a new location if the url is different.
   std::string url_string;
   if (update_props->HasKey(keys::kUrlKey)) {
     EXTENSION_FUNCTION_VALIDATE(update_props->GetString(
@@ skipping 523 matching lines @@
   // called for every API call the extension made.
   GotLanguage(language);
 }
 
 void DetectTabLanguageFunction::GotLanguage(const std::string& language) {
   result_.reset(Value::CreateStringValue(language.c_str()));
   SendResponse(true);
 
   Release();  // Balanced in Run()
 }