Create stub IdentityProvider

fix brave/browser-laptop#3398

auditor: @bridiver

atom/browser/autofill/atom_autofill_client.cc

@@ -17,6 +17,7 @@
 #include "components/user_prefs/user_prefs.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/common/origin_util.h"
+#include "google_apis/gaia/identity_provider.h"
 #include "native_mate/dictionary.h"
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(autofill::AtomAutofillClient);
@@ -52,6 +53,28 @@ struct Converter<autofill::Suggestion> {
 };
 }  // namespace mate
 
+class StubIdentityProvider : public IdentityProvider{
+ public:
+  StubIdentityProvider() {}
+  ~StubIdentityProvider() override {}
+
+  std::string GetActiveUsername() override {
+    return std::string();
+  };
+
+  std::string GetActiveAccountId() override {
+    return std::string();
+  ;}
+
+  OAuth2TokenService* GetTokenService() override {
+    return nullptr;
+  };
+
+  bool RequestLogin() override {
+    return false;
+  };
+};
+
 namespace autofill {
 
 AtomAutofillClient::AtomAutofillClient(content::WebContents* web_contents)
@@ -96,7 +119,10 @@ sync_driver::SyncService* AtomAutofillClient::GetSyncService() {
 }
 
 IdentityProvider* AtomAutofillClient::GetIdentityProvider() {
-  return nullptr;
+  if (!identity_provider_) {
+     identity_provider_.reset(new StubIdentityProvider());
+  }
+  return identity_provider_.get();
 }
 
 rappor::RapporService* AtomAutofillClient::GetRapporService() {

atom/browser/autofill/atom_autofill_client.h

@@ -28,6 +28,8 @@ namespace content {
 class WebContents;
 }
 
+class IdentityProvider;
+
 namespace autofill {
 
 class FormStructure;
@@ -91,6 +93,8 @@ class AtomAutofillClient
 
   base::WeakPtr<AutofillPopupDelegate> delegate_;
 
+  std::unique_ptr<IdentityProvider> identity_provider_;
+
   DISALLOW_COPY_AND_ASSIGN(AtomAutofillClient);
 };