Take 2 at implementing activeTab.

chrome/renderer/extensions/user_script_slave.cc

 // 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.
 
 #include "chrome/renderer/extensions/user_script_slave.h"
 
 #include <map>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 261 matching lines @@
     if (frame->parent() && !script->match_all_frames())
       continue;  // Only match subframes if the script declared it wanted to.
 
     const Extension* extension = extensions_->GetByID(script->extension_id());
 
     // Since extension info is sent separately from user script info, they can
     // be out of sync. We just ignore this situation.
     if (!extension)
       continue;
 
-    if (!extension->CanExecuteScriptOnPage(data_source_url, script, NULL))
+    // Content scripts are not tab-specific.
+    int kNoTabId = -1;
+    if (!extension->CanExecuteScriptOnPage(data_source_url,
+                                           kNoTabId,
+                                           script,
+                                           NULL)) {
       continue;
+    }
 
     // We rely on WebCore for CSS injection, but it's still useful to know how
     // many css files there are.
     if (location == UserScript::DOCUMENT_START)
       num_css += script->css_scripts().size();
 
     if (script->run_location() == location) {
       num_scripts += script->js_scripts().size();
       for (size_t j = 0; j < script->js_scripts().size(); ++j) {
         UserScript::File &file = script->js_scripts()[j];
@@ skipping 61 matching lines @@
     if (num_scripts)
       UMA_HISTOGRAM_TIMES("Extensions.InjectEnd_Time", timer.Elapsed());
   } else if (location == UserScript::DOCUMENT_IDLE) {
     UMA_HISTOGRAM_COUNTS_100("Extensions.InjectIdle_ScriptCount", num_scripts);
     if (num_scripts)
       UMA_HISTOGRAM_TIMES("Extensions.InjectIdle_Time", timer.Elapsed());
   } else {
     NOTREACHED();
   }
 }