Implemented a "Last Updated" field for the about page of Chrome OS.

BUG=117517
TEST=


Review URL: http://codereview.chromium.org/10038034

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@133840 0039d316-1c4b-4281-b951-d872f2087c98

base/sys_info.h

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -8,6 +8,8 @@
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
+#include "base/file_path.h"
+#include "base/time.h"
 
 #include <string>
 
@@ -61,7 +63,7 @@ class BASE_EXPORT SysInfo {
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
   // Returns the maximum SysV shared memory segment size.
   static size_t MaxSharedMemorySize();
-#endif
+#endif // defined(OS_POSIX) && !defined(OS_MACOSX)
 
 #if defined(OS_CHROMEOS)
   // Returns the name of the version entry we wish to look up in the
@@ -74,7 +76,10 @@ class BASE_EXPORT SysInfo {
                               int32* major_version,
                               int32* minor_version,
                               int32* bugfix_version);
-#endif
+
+  // Returns the path to the lsb-release file.
+  static FilePath GetLsbReleaseFilePath();
+#endif // defined(OS_CHROMEOS)
 };
 
 }  // namespace base

base/sys_info_chromeos.cc

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -113,4 +113,9 @@ void SysInfo::ParseLsbRelease(const std::string& lsb_release,
   }
 }
 
+// static
+FilePath SysInfo::GetLsbReleaseFilePath() {
+  return FilePath(kLinuxStandardBaseReleaseFile);
+}
+
 }  // namespace base

chrome/app/generated_resources.grd

@@ -5884,6 +5884,9 @@ Because search results are requested even while you're typing your query, your d
       <message name="IDS_ABOUT_VERSION_COMMAND_LINE" desc="label for the command line on the about:version page">
         Command Line
       </message>
+      <message name="IDS_ABOUT_VERSION_LAST_UPDATED" desc="label for date last updated on the about:version page">
+        Last Updated
+      </message>
       <message name="IDS_ABOUT_VERSION_EXECUTABLE_PATH" desc="label for the executable path on the about:version page">
         Executable Path
       </message>

chrome/browser/resources/help/help.css

@@ -90,3 +90,7 @@ body {
   margin-bottom: 0;
   overflow: hidden;
 }
+
+#last-updated-container.empty {
+  visibility: hidden;
+}

chrome/browser/resources/help/help.html

@@ -62,6 +62,10 @@
           <h3 i18n-content="commandLine"></h3>
           <div i18n-content="commandLineInfo" dir="ltr"></div>
         </section>
+        <section id="last-updated-container" class="empty">
+          <h3 i18n-content="lastUpdated"></h3>
+          <div id="last-updated"></div>
+        </section>
       </div>
       <button id="more-info-expander" class="link-button"
           i18n-content="showMoreInfo">

chrome/browser/resources/help/help.js

@@ -213,6 +213,16 @@ cr.define('help', function() {
     setReleaseChannel_: function(channel) {
       chrome.send('setReleaseTrack', [channel]);
     },
+
+    /**
+     * Sets the value of the "Last Updated" field of the "More Info" section.
+     * @param {String} lastUpdated The date of the last update.
+     * @private
+     */
+    setLastUpdated_: function(lastUpdated) {
+      $('last-updated-container').classList.remove('empty');
+      $('last-updated').textContent = lastUpdated;
+    },
   };
 
   HelpPage.setUpdateStatus = function(status, message) {
@@ -251,6 +261,10 @@ cr.define('help', function() {
     HelpPage.getInstance().setReleaseChannel_(channel);
   };
 
+  HelpPage.setLastUpdated = function(lastUpdated) {
+    HelpPage.getInstance().setLastUpdated_(lastUpdated);
+  }
+
   // Export
   return {
     HelpPage: HelpPage

chrome/browser/ui/webui/help/help_handler.cc

@@ -34,13 +34,18 @@
 #include "webkit/glue/webkit_glue.h"
 
 #if defined(OS_CHROMEOS)
+#include "base/i18n/time_formatting.h"
+#include "base/file_util_proxy.h"
+#include "base/sys_info.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "chrome/browser/chromeos/cros_settings.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/prefs/pref_service.h"
+#include "content/public/browser/browser_thread.h"
 #endif
 
 using base::ListValue;
+using content::BrowserThread;
 
 namespace {
 
@@ -90,12 +95,18 @@ bool CanChangeReleaseChannel() {
   return false;
 }
 
+// Pointer to a |StringValue| holding the date of the last update to Chromium
+// OS. Because this value is obtained by reading a file, it is cached here to
+// prevent the need to read from the file system multiple times unnecessarily.
+Value* g_last_updated_string = NULL;
+
 #endif  // defined(OS_CHROMEOS)
 
 }  // namespace
 
 HelpHandler::HelpHandler()
-    : version_updater_(VersionUpdater::Create()) {
+    : version_updater_(VersionUpdater::Create()),
+      ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)) {
 }
 
 HelpHandler::~HelpHandler() {
@@ -136,6 +147,7 @@ void HelpHandler::GetLocalizedValues(DictionaryValue* localized_strings) {
     { "webkit", IDS_WEBKIT },
     { "userAgent", IDS_ABOUT_VERSION_USER_AGENT },
     { "commandLine", IDS_ABOUT_VERSION_COMMAND_LINE },
+    { "lastUpdated", IDS_ABOUT_VERSION_LAST_UPDATED },
 #endif
 #if defined(OS_MACOSX)
     { "promote", IDS_ABOUT_CHROME_PROMOTE_UPDATER },
@@ -235,6 +247,19 @@ void HelpHandler::OnPageLoaded(const ListValue* args) {
       base::Value::CreateBooleanValue(CanChangeReleaseChannel()));
   web_ui()->CallJavascriptFunction(
       "help.HelpPage.updateEnableReleaseChannel", *can_change_channel_value);
+
+  if (g_last_updated_string == NULL) {
+    // If |g_last_updated_string| is |NULL|, the date has not yet been assigned.
+    // Get the date of the last lsb-release file modification.
+    base::FileUtilProxy::GetFileInfo(
+        BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE),
+        base::SysInfo::GetLsbReleaseFilePath(),
+        base::Bind(&HelpHandler::ProcessLsbFileInfo,
+                   weak_factory_.GetWeakPtr()));
+  } else {
+    web_ui()->CallJavascriptFunction("help.HelpPage.setLastUpdated",
+                                     *g_last_updated_string);
+  }
 #endif  // defined(OS_CHROMEOS)
 
   version_updater_->CheckForUpdate(
@@ -380,4 +405,32 @@ void HelpHandler::OnReleaseChannel(const std::string& channel) {
   web_ui()->CallJavascriptFunction(
       "help.HelpPage.updateSelectedChannel", *channel_string);
 }
+
+void HelpHandler::ProcessLsbFileInfo(
+    base::PlatformFileError error, const base::PlatformFileInfo& file_info) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  // If |g_last_updated_string| is not |NULL|, then the file's information has
+  // already been retrieved by another tab.
+  if (g_last_updated_string == NULL) {
+    base::Time time;
+    if (error == base::PLATFORM_FILE_OK) {
+      // Retrieves the approximate time at which Chrome OS was last updated.
+      // Each time a new build is created, /etc/lsb-release is modified with the
+      // new version numbers of the release.
+      time = file_info.last_modified;
+    } else {
+      // If the time of the last update cannot be retrieved, return and do not
+      // display the "Last Updated" section.
+      return;
+    }
+
+    // Note that this string will be internationalized.
+    string16 last_updated = base::TimeFormatFriendlyDate(time);
+    g_last_updated_string = Value::CreateStringValue(last_updated);
+  }
+
+  web_ui()->CallJavascriptFunction("help.HelpPage.setLastUpdated",
+                                   *g_last_updated_string);
+}
 #endif // defined(OS_CHROMEOS)

chrome/browser/ui/webui/help/help_handler.h

@@ -8,12 +8,14 @@
 #include <string>
 
 #include "base/compiler_specific.h"
+#include "base/memory/weak_ptr.h"
 #include "chrome/browser/ui/webui/help/version_updater.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_ui_message_handler.h"
 
 #if defined(OS_CHROMEOS)
+#include "base/platform_file.h"
 #include "chrome/browser/chromeos/version_loader.h"
 #endif  // defined(OS_CHROMEOS)
 
@@ -72,11 +74,17 @@ class HelpHandler : public content::WebUIMessageHandler,
   void OnOSFirmware(chromeos::VersionLoader::Handle handle,
                     std::string firmware);
   void OnReleaseChannel(const std::string& channel);
+
+  void ProcessLsbFileInfo(
+      base::PlatformFileError rv, const base::PlatformFileInfo& file_info);
 #endif
 
   // Specialized instance of the VersionUpdater used to update the browser.
   scoped_ptr<VersionUpdater> version_updater_;
 
+  // Used for callbacks.
+  base::WeakPtrFactory<HelpHandler> weak_factory_;
+
   // Used to observe notifications.
   content::NotificationRegistrar registrar_;