Don't send unnecessary ExtensionMsg_Loaded IPCs.

chrome/browser/extensions/api/permissions/permissions_apitest.cc

Index: chrome/browser/extensions/api/permissions/permissions_apitest.cc
diff --git a/chrome/browser/extensions/api/permissions/permissions_apitest.cc b/chrome/browser/extensions/api/permissions/permissions_apitest.cc
index 9b980729157723dd0fdc7d4e27d5f3daababb258..7d43a1e46d2a455500c68a6a4098e48b306c997e 100644
--- a/chrome/browser/extensions/api/permissions/permissions_apitest.cc
+++ b/chrome/browser/extensions/api/permissions/permissions_apitest.cc
@@ -195,4 +195,13 @@ IN_PROC_BROWSER_TEST_F(ExtensionApiTest, HostSubsets) {
   EXPECT_TRUE(RunExtensionTest("permissions/host_subsets")) << message_;
 }
 
+// Tests that requesting an optional permission from a background page, with
+// another window open, grants the permission and updates the bindings
+// (chrome.whatever, in this case chrome.storage). Regression test for

[Devlin, 2015/06/03 20:53:36]

The test seems to use chrome.alarms?

[not at google - send to devlin, 2015/06/03 21:53:03]

Done.

+// crbug.com/435141, see details there for trickyness.

[Devlin, 2015/06/03 20:53:37]

s/trickyness/trickiness

[not at google - send to devlin, 2015/06/03 21:53:03]

Done.

+IN_PROC_BROWSER_TEST_F(ExtensionApiTest, OptionalPermissionsUpdatesBindings) {
+  ASSERT_TRUE(RunExtensionTest("permissions/optional_updates_bindings"))

[Devlin, 2015/06/03 20:53:37]

I trust this test failed without this patch?

[not at google - send to devlin, 2015/06/03 21:53:03]

...

[Devlin, 2015/06/03 21:56:44]

Yeah, okay, that was silly.  I trust this test fails if we sent redundant IPCs,
as we did before this patch?

[not at google - send to devlin, 2015/06/03 22:05:36]

I'm not really sure how to test that without more or less going back to the
state before this patch :)

[Devlin, 2015/06/03 22:17:49]

You say that like it's hard. :P
git checkout origin -b test_api_regression
git checkout <whatever this branch is>
chrome/test/data/extensions/api_test/permissions/optional_updates_bindings
git checkout <whatever this branch is>
chrome/browser/extensions/api/permissions/permissions_apitest.cc

Done.

For the record, this does indeed fail. :)

(I only ask because if you say it's a regression test, it's good to make sure it
would have otherwise detected the failure.)

+      << message_;
+}
+
 }  // namespace extensions