Lazy background pages now load in response to message passing.

I refactored the pending event stuff so that it handles generic tasks. The
first enqueued task for an extension will start its lazy background page, and
tasks are run once the page finishes loading. Events and messages now share
this mechanism so that either one can activate the page.

BUG=81752
TEST=no

Review URL: https://chromiumcodereview.appspot.com/9704031

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@127216 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 39 insertions, 0 deletions

diff --git a/chrome/browser/extensions/lazy_background_page_apitest.cc b/chrome/browser/extensions/lazy_background_page_apitest.cc
index 45fef79..5c93462 100644
--- a/chrome/browser/extensions/lazy_background_page_apitest.cc
+++ b/chrome/browser/extensions/lazy_background_page_apitest.cc
@@ -47,6 +47,13 @@ class LazyBackgroundObserver {
     page_closed_.Wait();
   }
 
+  void WaitUntilLoaded() {
+    page_created_.Wait();
+  }
+  void WaitUntilClosed() {
+    page_closed_.Wait();
+  }
+
  private:
   ui_test_utils::WindowedNotificationObserver page_created_;
   ui_test_utils::WindowedNotificationObserver page_closed_;
@@ -327,6 +334,38 @@ IN_PROC_BROWSER_TEST_F(LazyBackgroundPageApiTest, IncognitoSplitMode) {
   }
 }
 
+// Tests that messages from the content script activate the lazy background
+// page, and keep it alive until all channels are closed.
+IN_PROC_BROWSER_TEST_F(LazyBackgroundPageApiTest, Messaging) {
+  ASSERT_TRUE(StartTestServer());
+  ASSERT_TRUE(LoadExtensionAndWait("messaging"));
+
+  // Lazy Background Page doesn't exist yet.
+  ExtensionProcessManager* pm =
+      browser()->profile()->GetExtensionProcessManager();
+  EXPECT_FALSE(pm->GetBackgroundHostForExtension(last_loaded_extension_id_));
+  EXPECT_EQ(1, browser()->tab_count());
+
+  // Navigate to a page that opens a message channel to the background page.
+  ResultCatcher catcher;
+  LazyBackgroundObserver lazybg;
+  ui_test_utils::NavigateToURL(
+      browser(), test_server()->GetURL("files/extensions/test_file.html"));
+  lazybg.WaitUntilLoaded();
+
+  // Background page got the content script's message and is still loaded
+  // until we close the channel.
+  EXPECT_TRUE(catcher.GetNextResult()) << catcher.message();
+  EXPECT_TRUE(pm->GetBackgroundHostForExtension(last_loaded_extension_id_));
+
+  // Navigate away, closing the message channel and therefore the background
+  // page.
+  ui_test_utils::NavigateToURL(browser(), GURL("about:blank"));
+  lazybg.WaitUntilClosed();
+
+  EXPECT_FALSE(pm->GetBackgroundHostForExtension(last_loaded_extension_id_));
+}
+
 // TODO: background page with timer.
 // TODO: background page that interacts with popup.
 // TODO: background page with menu.