Make all content scripts from an extension run in the same

chrome/renderer/user_script_slave.cc

 // Copyright (c) 2009 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/renderer/user_script_slave.h"
 
 #include "app/resource_bundle.h"
 #include "base/histogram.h"
 #include "base/logging.h"
 #include "base/perftimer.h"
@@ skipping 14 matching lines @@
 static const char kUserScriptHead[] = "(function (unsafeWindow) {\n";
 static const char kUserScriptTail[] = "\n})(window);";
 
 // Creates a convenient reference to a content script's parent extension.
 // TODO(mpcomplete): self.onConnect is deprecated.  Remove it at 1.0.
 // http://code.google.com/p/chromium/issues/detail?id=16356
 static const char kInitExtension[] =
     "chrome.extension = new chrome.Extension('%s');"
     "chrome.self.onConnect = chrome.extension.onConnect;";
 
+int UserScriptSlave::GetIsolatedWorldId(const std::string& extension_id) {
+  typedef std::map<std::string, int> IsolatedWorldMap;
+
+  static IsolatedWorldMap g_isolated_world_ids;
+  static int g_next_isolated_world_id = 1;
+
+  IsolatedWorldMap::iterator iter = g_isolated_world_ids.find(extension_id);
+  if (iter != g_isolated_world_ids.end())
+    return iter->second;
+
+  int new_id = g_next_isolated_world_id;
+  ++g_next_isolated_world_id;
+
+  // This map will tend to pile up over time, but realistically, you're never
+  // going to have enough extensions for it to matter.
+  g_isolated_world_ids[extension_id] = new_id;
+  return new_id;
+}
+
 UserScriptSlave::UserScriptSlave()
     : shared_memory_(NULL),
       script_deleter_(&scripts_),
       user_script_start_line_(0) {
   api_js_ = ResourceBundle::GetSharedInstance().GetRawDataResource(
                 IDR_GREASEMONKEY_API_JS);
 
   // Count the number of lines that will be injected before the user script.
   base::StringPiece::size_type pos = 0;
   while ((pos = api_js_.find('\n', pos)) != base::StringPiece::npos) {
@@ skipping 107 matching lines @@
         if (script->is_standalone()) {
           content.insert(0, kUserScriptHead);
           content += kUserScriptTail;
         }
         sources.push_back(
             WebScriptSource(WebString::fromUTF8(content), file.url()));
       }
     }
 
     if (!sources.empty()) {
+      int isolated_world_id = 0;
+
       if (script->is_standalone()) {
         // For standalone scripts, we try to emulate the Greasemonkey API.
         sources.insert(sources.begin(),
             WebScriptSource(WebString::fromUTF8(api_js_.as_string())));
       } else {
         // Setup chrome.self to contain an Extension object with the correct
         // ID.
         InsertInitExtensionCode(&sources, script->extension_id());
+        isolated_world_id = GetIsolatedWorldId(script->extension_id());
       }
 
-      frame->executeScriptInNewWorld(&sources.front(), sources.size(),
-                                     EXTENSION_GROUP_CONTENT_SCRIPTS);
+      frame->executeScriptInIsolatedWorld(
+          isolated_world_id, &sources.front(), sources.size(),
+          EXTENSION_GROUP_CONTENT_SCRIPTS);
     }
   }
 
   // Log debug info.
   if (location == UserScript::DOCUMENT_START) {
     UMA_HISTOGRAM_COUNTS_100("Extensions.InjectStart_CssCount", num_css);
     UMA_HISTOGRAM_COUNTS_100("Extensions.InjectStart_ScriptCount", num_scripts);
     UMA_HISTOGRAM_TIMES("Extensions.InjectStart_Time", timer.Elapsed());
   } else {
     UMA_HISTOGRAM_COUNTS_100("Extensions.InjectEnd_ScriptCount", num_scripts);
     UMA_HISTOGRAM_TIMES("Extensions.InjectEnd_Time", timer.Elapsed());
   }
 
   LOG(INFO) << "Injected " << num_scripts << " scripts and " << num_css <<
       "css files into " << frame->url().spec().data();
   return true;
 }