Show the Cast toolbar icon ephemerally when Cast is in use

chrome/browser/ui/toolbar/toolbar_actions_bar.cc

Index: chrome/browser/ui/toolbar/toolbar_actions_bar.cc
diff --git a/chrome/browser/ui/toolbar/toolbar_actions_bar.cc b/chrome/browser/ui/toolbar/toolbar_actions_bar.cc
index d60b27b960cc304c4dbace88b83b171766cd7323..f796b03119a1e44ddda4520cdc1bc329f15096dc 100644
--- a/chrome/browser/ui/toolbar/toolbar_actions_bar.cc
+++ b/chrome/browser/ui/toolbar/toolbar_actions_bar.cc
@@ -571,7 +571,8 @@ void ToolbarActionsBar::AddObserver(ToolbarActionsBarObserver* observer) {
 }
 
 void ToolbarActionsBar::RemoveObserver(ToolbarActionsBarObserver* observer) {
-  observers_.RemoveObserver(observer);
+  if (observers_.HasObserver(observer))

[msw, 2016/07/26 19:59:31]

Is something removing itself twice now? Can you fix that instead?

[Devlin, 2016/07/26 21:59:03]

+1

[takumif, 2016/07/28 20:04:11]

Done.

+    observers_.RemoveObserver(observer);
 }
 
 void ToolbarActionsBar::ShowToolbarActionBubble(
@@ -678,9 +679,11 @@ void ToolbarActionsBar::OnToolbarActionRemoved(const std::string& action_id) {
   // because the icon is just going to get re-added to the same location.
   // There is an exception if this is an off-the-record profile, and the
   // extension is no longer incognito-enabled.
-  if (!extensions::ExtensionSystem::Get(browser_->profile())
-           ->runtime_data()
-           ->IsBeingUpgraded(action_id) ||
+  if (ComponentToolbarActionsFactory::GetInstance()

[msw, 2016/07/26 19:59:31]

Is this check actually necessary? Wouldn't IsBeingUpgraded just return false,
achieving the same effect without this new check?

[Devlin, 2016/07/26 21:59:02]

Yes, it would.  Please remove this check.  ToolbarActionsBar should try to
remain relatively agnostic about extensions vs components.

[takumif, 2016/07/28 20:04:11]

Okay. In MRActionUnitTest, runtime_data() here is set to null (which I believe
is MockExtensionSystem::runtime_data()). Devlin, what would be a good way to
deal with that?

[Devlin, 2016/07/29 19:10:22]

Call CreateExtensionService() on TestExtensionSystem.  See other classes that
use CreateToolbarModelForProfile() for examples.

[takumif, 2016/08/02 04:58:41]

Thanks, did that.

+          ->IsComponentActionId(action_id) ||
+      !extensions::ExtensionSystem::Get(browser_->profile())
+          ->runtime_data()
+          ->IsBeingUpgraded(action_id) ||
       (browser_->profile()->IsOffTheRecord() &&
        !extensions::util::IsIncognitoEnabled(action_id, browser_->profile()))) {
     if (toolbar_actions_.size() > model_->visible_icon_count()) {