Move logic to clear ExtensionAction values to ExtensionActionAPI

chrome/browser/extensions/page_action_controller.cc

Index: chrome/browser/extensions/page_action_controller.cc
diff --git a/chrome/browser/extensions/page_action_controller.cc b/chrome/browser/extensions/page_action_controller.cc
index 8e39531404fb6229e7342e6f03043627271ccbde..3956072adabfc988485398f383d1746fd39c74ce 100644
--- a/chrome/browser/extensions/page_action_controller.cc
+++ b/chrome/browser/extensions/page_action_controller.cc
@@ -64,32 +64,8 @@ ExtensionAction::ShowAction PageActionController::OnClicked(
 }
 
 void PageActionController::OnNavigated() {
-  const ExtensionSet& extensions =
-      ExtensionRegistry::Get(web_contents_->GetBrowserContext())
-          ->enabled_extensions();
-  int tab_id = SessionTabHelper::IdForTab(web_contents_);
-  size_t num_current_actions = 0u;
-  for (ExtensionSet::const_iterator iter = extensions.begin();
-       iter != extensions.end();
-       ++iter) {
-    ExtensionAction* action = GetActionForExtension(*iter);
-    if (action) {
-      action->ClearAllValuesForTab(tab_id);
-      ++num_current_actions;
-    }
-  }
-
-  Profile* profile = GetProfile();
-  // Report the number of page actions for this profile, if we haven't already.
-  // TODO(rdevlin.cronin): This is wrong. Instead, it should record the number
-  // of page actions displayed per page.
-  if (!g_reported_for_profiles.Get().count(profile)) {

[Devlin, 2014/08/21 14:05:43]

From Other Comment:
"We wanted to know how common it is to have more than one page action show up at
the same time for any given navigation"

So, here we only log once per profile - which already means that we will only
log for a single page navigation (probably the new tab page, statistically). 
But, more importantly, we count an extension if we can GetActionForExtension(),
but that just forwards to ExtensionActionManager->GetPageAction(), which is
exactly what we use to check for LoadPageActions in InstalledLoader (and is
simply indicative of if an extension has a page action declared).

So...we just log the number of extensions with page actions for the given
profile.

That said, the metric you proposed sounds much better (hence the TODO I added
here awhile back ;))  I could probably make that metric and take this one out in
this patch set - SGTY?

[Finnur, 2014/08/21 14:19:18]

If that means killing this one and leaving the other, then yeah -- go for it.

-    UMA_HISTOGRAM_COUNTS_100("PageActionController.ExtensionsWithPageActions",
-                             num_current_actions);
-    g_reported_for_profiles.Get().insert(profile);
-  }
-
-  LocationBarController::NotifyChange(web_contents_);
+  // Clearing extension action values is handled in TabHelper, so nothing to
+  // do here.
 }
 
 void PageActionController::OnExtensionActionUpdated(