Connect UserStyleSheetWatcher to FileWatcher to have changes to

chrome/browser/user_style_sheet_watcher.cc

 // Copyright (c) 2010 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/user_style_sheet_watcher.h"
 
 #include "base/base64.h"
 #include "base/file_util.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/notification_type.h"
 
+namespace {
+
+// The subdirectory of the profile that contains the style sheet.
+const char kStyleSheetDir[] = "User StyleSheets";
+// The filename of the stylesheet.
+const char kUserStyleSheetFile[] = "Custom.css";
+
+}  // namespace
+
 UserStyleSheetWatcher::UserStyleSheetWatcher(const FilePath& profile_path)
     : profile_path_(profile_path),
       has_loaded_(false) {
   // Listen for when the first render view host is created.  If we load
   // too fast, the first tab won't hear the notification and won't get
   // the user style sheet.
   registrar_.Add(this, NotificationType::RENDER_VIEW_HOST_CREATED_FOR_TAB,
                  NotificationService::AllSources());
 }
 
 void UserStyleSheetWatcher::Observe(NotificationType type,
     const NotificationSource& source, const NotificationDetails& details) {
   DCHECK(type == NotificationType::RENDER_VIEW_HOST_CREATED_FOR_TAB);
 
   if (has_loaded_) {
     NotificationService::current()->Notify(
         NotificationType::USER_STYLE_SHEET_UPDATED,
         Source<UserStyleSheetWatcher>(this),
         NotificationService::NoDetails());
   }
 
   registrar_.RemoveAll();
 }
 
+void UserStyleSheetWatcher::OnFileChanged(const FilePath& path) {
+  ChromeThread::PostTask(ChromeThread::FILE, FROM_HERE,
+      NewRunnableMethod(this, &UserStyleSheetWatcher::LoadStyleSheet,
+                        profile_path_));
+}
+
 void UserStyleSheetWatcher::Init() {
   ChromeThread::PostTask(ChromeThread::FILE, FROM_HERE,
       NewRunnableMethod(this, &UserStyleSheetWatcher::LoadStyleSheet,
                         profile_path_));
 }
 
 void UserStyleSheetWatcher::LoadStyleSheet(const FilePath& profile_path) {
   DCHECK(ChromeThread::CurrentlyOn(ChromeThread::FILE));
   // We keep the user style sheet in a subdir so we can watch for changes
   // to the file.
-  FilePath style_sheet_dir = profile_path.AppendASCII("User StyleSheets");
+  FilePath style_sheet_dir = profile_path.AppendASCII(kStyleSheetDir);
   if (!file_util::DirectoryExists(style_sheet_dir)) {
     if (!file_util::CreateDirectory(style_sheet_dir))
       return;
   }
   // Create the file if it doesn't exist.
-  FilePath css_file = style_sheet_dir.AppendASCII("Custom.css");
+  FilePath css_file = style_sheet_dir.AppendASCII(kUserStyleSheetFile);
   if (!file_util::PathExists(css_file))
     file_util::WriteFile(css_file, "", 0);
 
   std::string css;
   bool rv = file_util::ReadFileToString(css_file, &css);
   GURL style_sheet_url;
-  if (rv) {
+  if (rv && !css.empty()) {
     std::string css_base64;
     rv = base::Base64Encode(css, &css_base64);
     if (rv) {
       // WebKit knows about data urls, so convert the file to a data url.
       const char kDataUrlPrefix[] = "data:text/css;charset=utf-8;base64,";
       style_sheet_url = GURL(kDataUrlPrefix + css_base64);
     }
   }
   ChromeThread::PostTask(ChromeThread::UI, FROM_HERE,
       NewRunnableMethod(this, &UserStyleSheetWatcher::SetStyleSheet,
                         style_sheet_url));
+
+  if (!file_watcher_.get()) {
+    file_watcher_.reset(new FileWatcher);
+    file_watcher_->Watch(profile_path_.AppendASCII(kStyleSheetDir)
+                         .AppendASCII(kUserStyleSheetFile), this);
+  }
 }
 
 void UserStyleSheetWatcher::SetStyleSheet(const GURL& url) {
   DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
 
   has_loaded_ = true;
   user_style_sheet_ = url;
   NotificationService::current()->Notify(
       NotificationType::USER_STYLE_SHEET_UPDATED,
       Source<UserStyleSheetWatcher>(this),
       NotificationService::NoDetails());
 }