Banish boilerplate. Profile-keyed API factory for extension API classes.

chrome/browser/extensions/api/processes/processes_api.cc

Index: chrome/browser/extensions/api/processes/processes_api.cc
diff --git a/chrome/browser/extensions/api/processes/processes_api.cc b/chrome/browser/extensions/api/processes/processes_api.cc
index 1779d9262519fb8ca218400e3547e8e5bf05a98c..94c2565b9faac3a97edd6d4b1da91d8de2d30c58 100644
--- a/chrome/browser/extensions/api/processes/processes_api.cc
+++ b/chrome/browser/extensions/api/processes/processes_api.cc
@@ -6,6 +6,7 @@
 
 #include "base/callback.h"
 #include "base/json/json_writer.h"
+#include "base/lazy_instance.h"
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/string_number_conversions.h"
@@ -13,7 +14,6 @@
 #include "base/values.h"
 
 #include "chrome/browser/extensions/api/processes/processes_api_constants.h"
-#include "chrome/browser/extensions/api/processes/processes_api_factory.h"
 #include "chrome/browser/extensions/api/tabs/tabs_constants.h"
 #include "chrome/browser/extensions/event_router.h"
 #include "chrome/browser/extensions/extension_function_registry.h"
@@ -506,7 +506,7 @@ void ProcessesAPI::Shutdown() {
 
 // static
 ProcessesAPI* ProcessesAPI::Get(Profile* profile) {
-  return ProcessesAPIFactory::GetForProfile(profile);
+  return ProfileKeyedAPIFactory<ProcessesAPI>::GetForProfile(profile);
 }
 
 ProcessesEventRouter* ProcessesAPI::processes_event_router() {
@@ -528,6 +528,15 @@ void ProcessesAPI::OnListenerRemoved(const EventListenerInfo& details) {
   processes_event_router()->ListenerRemoved();
 }
 
+static base::LazyInstance<ProfileKeyedAPIFactory<ProcessesAPI> >
+g_factory = LAZY_INSTANCE_INITIALIZER;
+
+template <>
+ProfileKeyedAPIFactory<ProcessesAPI>*

[Jeffrey Yasskin, 2012/12/22 00:16:04]

You should declare this specialization in processes_api.h (just after the
definition of ProcessesAPI). Since there's no default template definition, you
won't get undefined behavior by failing to declare it, but it's a good habit to
get into for when there is a default definition.

Document the code you use in the comment for
ProfileKeyedApiFactory::GetInstance().

[Yoyo Zhou, 2012/12/26 17:46:33]

Honestly, I was surprised to find that not declaring it in the header worked in
the first place.

[Jeffrey Yasskin, 2012/12/26 19:21:55]

Yeah, the biggest problem with missing declarations for explicit specializations
is that forgetting them will often work for the person checking in the code, and
then break for someone else, later.

+ProfileKeyedAPIFactory<ProcessesAPI>::GetInstance() {
+  return &g_factory.Get();
+}
+
 GetProcessIdForTabFunction::GetProcessIdForTabFunction() : tab_id_(-1) {
 }