Identity API: defer loading component app

chrome/browser/extensions/api/identity/web_auth_flow.cc

Index: chrome/browser/extensions/api/identity/web_auth_flow.cc
diff --git a/chrome/browser/extensions/api/identity/web_auth_flow.cc b/chrome/browser/extensions/api/identity/web_auth_flow.cc
index d4347d445f2a7cce584c07b5b8ee571676888c9c..0621e65c27ab66aa718758a2d2947c8c3d53bf65 100644
--- a/chrome/browser/extensions/api/identity/web_auth_flow.cc
+++ b/chrome/browser/extensions/api/identity/web_auth_flow.cc
@@ -7,6 +7,9 @@
 #include "base/location.h"
 #include "base/message_loop.h"
 #include "base/utf_string_conversions.h"
+#include "chrome/browser/extensions/component_loader.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_navigator.h"
@@ -20,6 +23,7 @@
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/page_transition_types.h"
 #include "googleurl/src/gurl.h"
+#include "grit/browser_resources.h"
 #include "ui/base/window_open_disposition.h"
 
 using content::LoadNotificationDetails;
@@ -66,6 +70,17 @@ WebAuthFlow::~WebAuthFlow() {
 }
 
 void WebAuthFlow::Start() {
+  static bool is_component_loaded = false;

[Matt Perry, 2013/05/29 00:39:28]

This isn't multi-profile safe.

[Michael Courage, 2013/05/29 00:49:37]

Good point. Is it reasonable/cheap to just do this unconditionally? It looked to
me like a lot of stuff was happening behind that Add call, so I threw in this
conditional. Seems like I should use a profile keyed service unless there is
some simpler way.

[Matt Perry, 2013/05/29 00:53:38]

This will actually cause the app to reload, which it's probably best to avoid.
Can you use ComponentLoader::Exists? You need the app ID, but that should be
known.

[Michael Courage, 2013/05/29 01:49:53]

ComponentLoader::Exists will do the trick, thanks.

It occurs to me that I really ought to put this code in
https://codereview.chromium.org/15897006/, which is where WebAuthFlow will
actually make use of the component app. I'll do that and just keep this CL
focused on fixing the memory issue.

+  if (!is_component_loaded) {
+    extensions::ExtensionSystem* extension_system =
+        extensions::ExtensionSystem::Get(profile_);
+    ExtensionService* extension_service = extension_system->extension_service();
+    extension_service->component_loader()->Add(
+        IDR_IDENTITY_API_SCOPE_APPROVAL_MANIFEST,
+        base::FilePath(FILE_PATH_LITERAL("identity_scope_approval_dialog")));
+    is_component_loaded = true;
+  }
+
   contents_ = CreateWebContents();
   WebContentsObserver::Observe(contents_);