Fix bug when CryptAuth requests are made with an empty protobuf serialization.

Do fix this edge case, we refactor OAuth2ApiCallFlow to allow overriding the
RequestType of the API call.

BUG=516849
TEST=unit tests

Review URL: https://codereview.chromium.org/1267393002

Cr-Commit-Position: refs/heads/master@{#342022}

3 files changed, 23 insertions, 4 deletions

diff --git a/components/proximity_auth/cryptauth/cryptauth_api_call_flow.cc b/components/proximity_auth/cryptauth/cryptauth_api_call_flow.cc
index c72e867..6f0f7f6 100644
--- a/components/proximity_auth/cryptauth/cryptauth_api_call_flow.cc
+++ b/components/proximity_auth/cryptauth/cryptauth_api_call_flow.cc
@@ -49,6 +49,11 @@ std::string CryptAuthApiCallFlow::CreateApiCallBodyContentType() {
   return "application/x-protobuf";
 }
 
+net::URLFetcher::RequestType CryptAuthApiCallFlow::GetRequestTypeForBody(
+    const std::string& body) {
+  return net::URLFetcher::POST;
+}
+
 void CryptAuthApiCallFlow::ProcessApiCallSuccess(
     const net::URLFetcher* source) {
   std::string serialized_response;
diff --git a/components/proximity_auth/cryptauth/cryptauth_api_call_flow.h b/components/proximity_auth/cryptauth/cryptauth_api_call_flow.h
index f351aed..76ec6cb 100644
--- a/components/proximity_auth/cryptauth/cryptauth_api_call_flow.h
+++ b/components/proximity_auth/cryptauth/cryptauth_api_call_flow.h
@@ -49,6 +49,8 @@ class CryptAuthApiCallFlow : public OAuth2ApiCallFlow {
   GURL CreateApiCallUrl() override;
   std::string CreateApiCallBody() override;
   std::string CreateApiCallBodyContentType() override;
+  net::URLFetcher::RequestType GetRequestTypeForBody(
+      const std::string& body) override;
   void ProcessApiCallSuccess(const net::URLFetcher* source) override;
   void ProcessApiCallFailure(const net::URLFetcher* source) override;
 
diff --git a/components/proximity_auth/cryptauth/cryptauth_api_call_flow_unittest.cc b/components/proximity_auth/cryptauth/cryptauth_api_call_flow_unittest.cc
index d7a15b6..dadbfda 100644
--- a/components/proximity_auth/cryptauth/cryptauth_api_call_flow_unittest.cc
+++ b/components/proximity_auth/cryptauth/cryptauth_api_call_flow_unittest.cc
@@ -37,14 +37,18 @@ class ProximityAuthCryptAuthApiCallFlowTest
   }
 
   void StartApiCallFlow() {
+    StartApiCallFlowWithRequest(kSerializedRequestProto);
+  }
+
+  void StartApiCallFlowWithRequest(const std::string& serialized_request) {
     flow_.Start(GURL(kRequestUrl), url_request_context_getter_.get(),
-                "access_token", kSerializedRequestProto,
+                "access_token", serialized_request,
                 base::Bind(&ProximityAuthCryptAuthApiCallFlowTest::OnResult,
                            base::Unretained(this)),
                 base::Bind(&ProximityAuthCryptAuthApiCallFlowTest::OnError,
                            base::Unretained(this)));
     // URLFetcher object for the API request should be created.
-    CheckCryptAuthHttpRequest();
+    CheckCryptAuthHttpRequest(serialized_request);
   }
 
   void OnResult(const std::string& result) {
@@ -57,10 +61,10 @@ class ProximityAuthCryptAuthApiCallFlowTest
     error_message_.reset(new std::string(error_message));
   }
 
-  void CheckCryptAuthHttpRequest() {
+  void CheckCryptAuthHttpRequest(const std::string& serialized_request) {
     ASSERT_TRUE(url_fetcher_);
     EXPECT_EQ(GURL(kRequestUrl), url_fetcher_->GetOriginalURL());
-    EXPECT_EQ(kSerializedRequestProto, url_fetcher_->upload_data());
+    EXPECT_EQ(serialized_request, url_fetcher_->upload_data());
 
     net::HttpRequestHeaders request_headers;
     url_fetcher_->GetExtraRequestHeaders(&request_headers);
@@ -128,6 +132,14 @@ TEST_F(ProximityAuthCryptAuthApiCallFlowTest, RequestStatus500) {
 }
 
 // The empty string is a valid protocol buffer message serialization.
+TEST_F(ProximityAuthCryptAuthApiCallFlowTest, RequestWithNoBody) {
+  StartApiCallFlowWithRequest(std::string());
+  CompleteCurrentRequest(net::OK, net::HTTP_OK, kSerializedResponseProto);
+  EXPECT_EQ(kSerializedResponseProto, *result_);
+  EXPECT_FALSE(error_message_);
+}
+
+// The empty string is a valid protocol buffer message serialization.
 TEST_F(ProximityAuthCryptAuthApiCallFlowTest, ResponseWithNoBody) {
   StartApiCallFlow();
   CompleteCurrentRequest(net::OK, net::HTTP_OK, std::string());