Change in the response format from Per User Topic server.

The response format has changed. The CL implements the
change on the client.
* renaming "private_topic_name" property to "privateTopicName"

Bug: 863816, 801985
Change-Id: I7e65b095c3764f73e928a0fa0a2fb5da461eb223
Reviewed-on: https://chromium-review.googlesource.com/1146725Reviewed-by: Pavel Yatsuk <pavely@chromium.org>
Reviewed-by: Jan Krcal <jkrcal@chromium.org>
Commit-Queue: Tatiana Gornak <melandory@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577888}

components/invalidation/impl/per_user_topic_registration_manager_unittest.cc

@@ -137,7 +137,7 @@ TEST_F(PerUserTopicRegistrationManagerTest, ShouldUpdateRegisteredIds) {
 
   std::string response_body = R"(
     {
-      "private_topic_name": "test-pr"
+      "privateTopicName": "test-pr"
     }
   )";
 

components/invalidation/impl/per_user_topic_registration_request.cc

@@ -17,7 +17,7 @@ using net::URLRequestStatus;
 
 namespace {
 
-const char kPrivateTopicNameKey[] = "private_topic_name";
+const char kPrivateTopicNameKey[] = "privateTopicName";
 
 base::Value* GetPrivateTopicName(base::Value* value) {
   if (!value || !value->is_dict()) {

components/invalidation/impl/per_user_topic_registration_request_unittest.cc

@@ -124,7 +124,7 @@ TEST_F(PerUserTopicRegistrationRequestTest, ShouldSubscribeWithoutErrors) {
           .Build();
   std::string response_body = R"(
     {
-      "private_topic_name": "test-pr"
+      "privateTopicName": "test-pr"
     }
   )";
 
@@ -166,7 +166,7 @@ TEST_F(PerUserTopicRegistrationRequestTest,
           .Build();
   std::string response_body = R"(
     {
-      "private_topic_name": "test-pr"
+      "privateTopicName": "test-pr"
     }
   )";