Experimental app list: Custom launcher pages have app APIs and style.

chrome/browser/ui/app_list/app_list_view_delegate.cc

Index: chrome/browser/ui/app_list/app_list_view_delegate.cc
diff --git a/chrome/browser/ui/app_list/app_list_view_delegate.cc b/chrome/browser/ui/app_list/app_list_view_delegate.cc
index 7af49bd8ab2e09fe566580e2dec68b9d91ad378a..2d2f3af90f2952860b84b18db71f618dc4ab5332 100644
--- a/chrome/browser/ui/app_list/app_list_view_delegate.cc
+++ b/chrome/browser/ui/app_list/app_list_view_delegate.cc
@@ -13,6 +13,7 @@
 #include "base/stl_util.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_notification_types.h"
+#include "chrome/browser/extensions/chrome_extension_web_contents_observer.h"
 #include "chrome/browser/profiles/profile_info_cache.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/search/hotword_service.h"
@@ -164,6 +165,10 @@ AppListViewDelegate::AppListViewDelegate(Profile* profile,
     } else {
       content::WebContents::CreateParams params(profile_);
       custom_page_web_contents_.reset(content::WebContents::Create(params));
+      // This observer will activate the extension when it is navigated to,
+      // which allows Dispatcher to give it the proper context.

[not at google - send to devlin, 2014/07/07 14:50:10]

creating a [Chrome]ExtensionWebContentsObserver does more than just set up the
context, it makes the entire extension infrastructure work.

[Matt Giuca, 2014/07/09 15:05:30]

Done.

+      extensions::ChromeExtensionWebContentsObserver::CreateForWebContents(
+          custom_page_web_contents_.get());
       custom_page_web_contents_->GetController().LoadURL(
           custom_launcher_page_url,
           content::Referrer(),