[GCM] DCHECK should not be used since it will skip the code inside

BUG=424697
TEST=Test added

Review URL: https://codereview.chromium.org/659393003

Cr-Commit-Position: refs/heads/master@{#300161}

components/gcm_driver/gcm_channel_status_request.cc

@@ -60,7 +60,9 @@ void GCMChannelStatusRequest::Start() {
   sync_pb::ExperimentStatusRequest proto_data;
   proto_data.add_experiment_name(kGCMChannelTag);
   std::string upload_data;
-  DCHECK(proto_data.SerializeToString(&upload_data));
+  if (!proto_data.SerializeToString(&upload_data)) {
+     NOTREACHED();
+  }
 
   url_fetcher_.reset(
       net::URLFetcher::Create(request_url, net::URLFetcher::POST, this));

components/gcm_driver/gcm_channel_status_request.h

@@ -7,6 +7,7 @@
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
+#include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
@@ -49,6 +50,8 @@ class GCMChannelStatusRequest : public net::URLFetcherDelegate {
   static int min_poll_interval_seconds();
 
  private:
+  FRIEND_TEST_ALL_PREFIXES(GCMChannelStatusRequestTest, RequestData);
+
   // Overridden from URLFetcherDelegate:
   virtual void OnURLFetchComplete(const net::URLFetcher* source) override;
 

components/gcm_driver/gcm_channel_status_request_unittest.cc

@@ -108,6 +108,30 @@ void GCMChannelStatusRequestTest::OnRequestCompleted(
   poll_interval_seconds_ = poll_interval_seconds;
 }
 
+TEST_F(GCMChannelStatusRequestTest, RequestData) {
+  StartRequest();
+
+  net::TestURLFetcher* fetcher = url_fetcher_factory_.GetFetcherByID(0);
+  ASSERT_TRUE(fetcher);
+
+  EXPECT_EQ(GURL(request_->channel_status_request_url_),
+            fetcher->GetOriginalURL());
+
+  net::HttpRequestHeaders headers;
+  fetcher->GetExtraRequestHeaders(&headers);
+  std::string user_agent_header;
+  headers.GetHeader("User-Agent", &user_agent_header);
+  EXPECT_FALSE(user_agent_header.empty());
+  EXPECT_EQ(request_->user_agent_, user_agent_header);
+
+  std::string upload_data = fetcher->upload_data();
+  EXPECT_FALSE(upload_data.empty());
+  sync_pb::ExperimentStatusRequest proto_data;
+  proto_data.ParseFromString(upload_data);
+  EXPECT_EQ(1, proto_data.experiment_name_size());
+  EXPECT_EQ("gcm_channel", proto_data.experiment_name(0));
+}
+
 TEST_F(GCMChannelStatusRequestTest, ResponseHttpStatusNotOK) {
   StartRequest();
   SetResponseStatusAndString(net::HTTP_UNAUTHORIZED, "");