Allow chrome.debugger API to attach to extension background pages.

chrome/test/data/extensions/api_test/debugger/background.js

Index: chrome/test/data/extensions/api_test/debugger/background.js
diff --git a/chrome/test/data/extensions/api_test/debugger/background.js b/chrome/test/data/extensions/api_test/debugger/background.js
index 0ca46c96a3bb130dba39384b31f4233213b97be4..78c2d33507f045aba14947bf41c986b4f0761c07 100644
--- a/chrome/test/data/extensions/api_test/debugger/background.js
+++ b/chrome/test/data/extensions/api_test/debugger/background.js
@@ -98,6 +98,18 @@ chrome.test.runTests([
           fail("Can not attach to the page with the \"chrome://\" scheme."));
       chrome.tabs.remove(tab.id);
     });
-  }
+  },
+
+  function attachToMissing() {
+    var missingDebuggee = {tabId: -1};
+    chrome.debugger.attach(missingDebuggee, protocolVersion,
+        fail("No tab with given id " + missingDebuggee.tabId + "."));
+  },
 
+  function attachToExtension() {

[pfeldman, 2013/02/20 14:58:39]

attachToExtensionWithNoSilentFlag

[Vladislav Kaznacheev, 2013/02/20 15:24:50]

Done.

+    debuggeeExtension = {extensionId: "foo"};
+    chrome.debugger.attach(debuggeeExtension, protocolVersion,
+        fail("Cannot attach to an extension, " +
+            "--extension-debugging-silent command line option required."));
+  },
 ]);