Add support for GCM subtypes to desktop Instance ID implementation

google_apis/gcm/engine/unregistration_request.cc

Index: google_apis/gcm/engine/unregistration_request.cc
diff --git a/google_apis/gcm/engine/unregistration_request.cc b/google_apis/gcm/engine/unregistration_request.cc
index bd225892a79709b44942df3719239c2c7e437adb..8b410d15895d9c2aaa654a84a8f7e0d1422b6da7 100644
--- a/google_apis/gcm/engine/unregistration_request.cc
+++ b/google_apis/gcm/engine/unregistration_request.cc
@@ -29,7 +29,8 @@ namespace {
 const char kRequestContentType[] = "application/x-www-form-urlencoded";
 
 // Request constants.
-const char kAppIdKey[] = "app";
+const char kCategoryKey[] = "app";
+const char kSubtypeKey[] = "X-subtype";
 const char kDeleteKey[] = "delete";
 const char kDeleteValue[] = "true";
 const char kDeviceIdKey[] = "device";
@@ -37,10 +38,17 @@ const char kLoginHeader[] = "AidLogin";
 
 }  // namespace
 
-UnregistrationRequest::RequestInfo::RequestInfo(uint64_t android_id,
-                                                uint64_t security_token,
-                                                const std::string& app_id)
-    : android_id(android_id), security_token(security_token), app_id(app_id) {
+UnregistrationRequest::RequestInfo::RequestInfo(
+    uint64_t android_id,
+    uint64_t security_token,
+    const std::string& app_id,
+    bool use_subtype,
+    const std::string& category_for_subtypes)
+    : android_id(android_id),
+      security_token(security_token),
+      app_id(app_id),
+      use_subtype(use_subtype),
+      category_for_subtypes(category_for_subtypes) {
   DCHECK(android_id != 0UL);
   DCHECK(security_token != 0UL);
 }
@@ -109,12 +117,17 @@ void UnregistrationRequest::BuildRequestHeaders(std::string* extra_headers) {
       std::string(kLoginHeader) + " " +
           base::Uint64ToString(request_info_.android_id) + ":" +
           base::Uint64ToString(request_info_.security_token));
-  headers.SetHeader(kAppIdKey, request_info_.app_id);
   *extra_headers = headers.ToString();
 }
 
 void UnregistrationRequest::BuildRequestBody(std::string* body) {
-  BuildFormEncoding(kAppIdKey, request_info_.app_id, body);
+  if (request_info_.use_subtype) {
+    BuildFormEncoding(kCategoryKey, request_info_.category_for_subtypes, body);
+    BuildFormEncoding(kSubtypeKey, request_info_.app_id, body);
+  } else {
+    BuildFormEncoding(kCategoryKey, request_info_.app_id, body);
+  }
+
   BuildFormEncoding(kDeviceIdKey,
                     base::Uint64ToString(request_info_.android_id),
                     body);