Integrate UI with authentication flow.

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 4ebebde648c30cfb8a3c03536604343eb4b982d8..2f75beb8aa188223dd3610826ae5f26ab650378f 100644
--- a/blimp/client/core/blimp_client_context_impl.cc
+++ b/blimp/client/core/blimp_client_context_impl.cc
@@ -95,10 +95,7 @@ std::unique_ptr<BlimpContents> BlimpClientContextImpl::CreateBlimpContents() {
 void BlimpClientContextImpl::Connect() {
   // Lazy initialization of IdentitySource.

[David Trainor- moved to gerrit, 2016/08/30 20:46:29]

Can this just call GetIdentitySource()->Connect()?

[xingliu, 2016/08/30 22:27:36]

Done.

   if (!identity_source_) {
-    identity_source_ = base::MakeUnique<IdentitySource>(
-        delegate_,
-        base::Bind(&BlimpClientContextImpl::ConnectToAssignmentSource,
-                   base::Unretained(this)));
+    CreateIdentitySource();
   }
 
   // Start Blimp authentication flow. The OAuth2 token will be used in
@@ -106,6 +103,13 @@ void BlimpClientContextImpl::Connect() {
   identity_source_->Connect();
 }
 
+IdentitySource* BlimpClientContextImpl::GetIdentitySource() {
+  if (!identity_source_) {
+    CreateIdentitySource();
+  }
+  return identity_source_.get();
+}
+
 void BlimpClientContextImpl::ConnectToAssignmentSource(
     const std::string& client_auth_token) {
   if (!assignment_source_) {
@@ -165,5 +169,11 @@ void BlimpClientContextImpl::RegisterFeatures() {
                                             tab_control_feature_.get()));
 }
 
+void BlimpClientContextImpl::CreateIdentitySource() {
+  identity_source_ = base::MakeUnique<IdentitySource>(
+      delegate_, base::Bind(&BlimpClientContextImpl::ConnectToAssignmentSource,
+                            base::Unretained(this)));
+}
+
 }  // namespace client
 }  // namespace blimp