Support Component Actions in the toolbar.

chrome/browser/ui/toolbar/component_toolbar_actions_factory.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/toolbar/component_toolbar_actions_factory.h"
 
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "chrome/browser/ui/toolbar/media_router_action.h"
 #include "chrome/browser/ui/toolbar/toolbar_action_view_controller.h"
 #include "chrome/common/chrome_switches.h"
 #include "extensions/common/feature_switch.h"
 
 namespace {
 
 ComponentToolbarActionsFactory* testing_factory_ = nullptr;
 
 base::LazyInstance<ComponentToolbarActionsFactory> lazy_factory =
     LAZY_INSTANCE_INITIALIZER;
 
 }  // namespace
 
+// static
+const char ComponentToolbarActionsFactory::kMediaRouterActionId[] =
+    "media_router_action";
+const char ComponentToolbarActionsFactory::kActionIdForTesting[] =
+    "mock_action";
+
 ComponentToolbarActionsFactory::ComponentToolbarActionsFactory()
     : num_component_actions_(-1) {}
 ComponentToolbarActionsFactory::~ComponentToolbarActionsFactory() {}
 
 // static
 ComponentToolbarActionsFactory* ComponentToolbarActionsFactory::GetInstance() {
   return testing_factory_ ? testing_factory_ : &lazy_factory.Get();
 }
 
+// static
+scoped_ptr<std::vector<std::string>>
+ComponentToolbarActionsFactory::GetComponentIds() {

[Peter Kasting, 2015/08/11 19:10:49]

It looks like this only ever returns 0 or 1 elements.  Can we just return a
string instead?  Or will this return more than one element in the future?

If not, do we really need to return a scoped_ptr?  It seems like it would be
simpler to just return the vector by copy (and stack-allocate it in this
function).

[apacible, 2015/08/12 05:26:44]

In the future, we'll be returning more than one element if/as more features
switch to having a component toolbar action. Devlin has more background on what
other features may have upcoming plans for this.

[Peter Kasting, 2015/08/12 07:13:45]

OK.  I still think returning the vector by copy might be better, but I don't
care much, and you're in a better position to evaluate.

[apacible, 2015/08/15 08:46:40]

Acknowledged.

+  scoped_ptr<std::vector<std::string>> component_ids(
+      new std::vector<std::string>);
+
+  // This is currently behind the extension-action-redesign flag, as it is
+  // designed for the new toolbar

[Peter Kasting, 2015/08/11 19:10:49]

Nit: Comments should have trailing periods.

[apacible, 2015/08/12 05:26:44]

Done.

+  if (!extensions::FeatureSwitch::extension_action_redesign()->IsEnabled())
+    return component_ids.Pass();
+
+  if (testing_factory_) {
+    component_ids->push_back(
+        ComponentToolbarActionsFactory::kActionIdForTesting);
+  } else {
+#if defined(ENABLE_MEDIA_ROUTER)
+    if (switches::MediaRouterEnabled()) {
+      component_ids->push_back(
+          ComponentToolbarActionsFactory::kMediaRouterActionId);
+    }
+#endif  // ENABLE_MEDIA_ROUTER
+  }
+
+  return component_ids.Pass();
+}
+
 ScopedVector<ToolbarActionViewController>
 ComponentToolbarActionsFactory::GetComponentToolbarActions(Browser* browser) {
   ScopedVector<ToolbarActionViewController> component_actions;
 
   // This is currently behind the extension-action-redesign flag, as it is
   // designed for the new toolbar.
   if (!extensions::FeatureSwitch::extension_action_redesign()->IsEnabled())
     return component_actions.Pass();
 
   // Add component toolbar actions here.
   // This current design means that the ComponentToolbarActionsFactory is aware
   // of all actions. Since we should *not* have an excessive amount of these
   // (since each will have an action in the toolbar or overflow menu), this
   // should be okay. If this changes, we should rethink this design to have,
   // e.g., RegisterChromeAction().
 
 #if defined(ENABLE_MEDIA_ROUTER)
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          ::switches::kEnableMediaRouter)) {
+  if (switches::MediaRouterEnabled())
     component_actions.push_back(new MediaRouterAction(browser));
-  }
 #endif
 
   return component_actions.Pass();
 }
 
-int ComponentToolbarActionsFactory::GetNumComponentActions(Browser* browser) {
+int ComponentToolbarActionsFactory::GetNumComponentActions() {
   if (num_component_actions_ == -1)

[Peter Kasting, 2015/08/11 19:10:49]

This member variable seems like over-optimization.  GetComponentIds() is
reasonably cheap, why not just always call that?

In fact, at that point, why not just eliminate this function entirely and have
callers always just get the vector?

[apacible, 2015/08/12 05:26:44]

Eliminated GetNumComponentActions().

-    num_component_actions_ = GetComponentToolbarActions(browser).size();
+    num_component_actions_ = GetComponentIds()->size();
 
   return num_component_actions_;
 }
 
 // static
 void ComponentToolbarActionsFactory::SetTestingFactory(
     ComponentToolbarActionsFactory* factory) {
   testing_factory_ = factory;
 }