Migrate TabControlFeature from 0.5 to 0.6

blimp/client/core/blimp_client_context_impl.cc

Index: blimp/client/core/blimp_client_context_impl.cc
diff --git a/blimp/client/core/blimp_client_context_impl.cc b/blimp/client/core/blimp_client_context_impl.cc
index 076fc78f34ea64ed7f5f8af03e5d9688d9169896..bfb6ec5848dc94cdc29f7866bf6a874d39417554 100644
--- a/blimp/client/core/blimp_client_context_impl.cc
+++ b/blimp/client/core/blimp_client_context_impl.cc
@@ -9,6 +9,7 @@
 #include "base/message_loop/message_loop.h"
 #include "base/threading/sequenced_task_runner_handle.h"
 #include "blimp/client/core/contents/blimp_contents_impl.h"
+#include "blimp/client/core/contents/blimp_contents_manager.h"
 #include "blimp/client/core/session/cross_thread_network_event_observer.h"
 #include "blimp/client/public/blimp_client_context_delegate.h"
 
@@ -37,6 +38,7 @@ BlimpClientContextImpl::BlimpClientContextImpl(
     scoped_refptr<base::SingleThreadTaskRunner> io_thread_task_runner)
     : BlimpClientContext(),
       io_thread_task_runner_(io_thread_task_runner),
+      blimp_contents_manager_(new BlimpContentsManager),
       weak_factory_(this) {
   blimp_connection_statistics_ = new BlimpConnectionStatistics();
   net_components_.reset(new ClientNetworkComponents(
@@ -66,7 +68,7 @@ void BlimpClientContextImpl::SetDelegate(BlimpClientContextDelegate* delegate) {
 
 std::unique_ptr<BlimpContents> BlimpClientContextImpl::CreateBlimpContents() {
   std::unique_ptr<BlimpContents> blimp_contents =
-      base::MakeUnique<BlimpContentsImpl>();
+      blimp_contents_manager_->CreateBlimpContents();
   delegate_->AttachBlimpContentsHelpers(blimp_contents.get());

[nyquist, 2016/08/05 23:03:22]

This call to the delegate is part of the public API, so we have to ensure that
we never expose BlimpContents that don't have had this call.

[Menglin, 2016/08/05 23:37:15]

Maybe define
BlimpContentsManager::CreateBlimpContents(BlimpClientContextDelegate*) ? so that
we essentially can move this line to
CreateBlimpContents(BlimpClientContextDelegate*) ?

[David Trainor- moved to gerrit, 2016/08/06 04:25:39]

Saw you two talked about it and decided this was okay.  I think you both have
good points.  It's probably fine to keep it this way, it kind of makes sense
because the delegate is part of the contract with BlimpClientContext and we
could probably argue that the manager shouldn't need to care about helpers...

It is a bit scary being able to create BlimpContents without helpers, but I
think WebContents has this issue currently as well.  BlimpContents doesn't
*need* helpers, they're just helping :).

   return blimp_contents;
 }