Add support for GCM subtypes to desktop Instance ID implementation

components/gcm_driver/gcm_desktop_utils.cc

Index: components/gcm_driver/gcm_desktop_utils.cc
diff --git a/components/gcm_driver/gcm_desktop_utils.cc b/components/gcm_driver/gcm_desktop_utils.cc
index 332ad32a6676ca9b0ff5133821723d25b65167f3..4bf14ac3080ef606d05cf71ac3d55310ad15165b 100644
--- a/components/gcm_driver/gcm_desktop_utils.cc
+++ b/components/gcm_driver/gcm_desktop_utils.cc
@@ -8,12 +8,19 @@
 
 #include "base/command_line.h"
 #include "base/sequenced_task_runner.h"
+#include "base/strings/string_piece.h"
+#include "base/strings/string_util.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "build/build_config.h"
+#include "components/gcm_driver/gcm_client.h"
 #include "components/gcm_driver/gcm_client_factory.h"
 #include "components/gcm_driver/gcm_driver.h"
 #include "components/gcm_driver/gcm_driver_desktop.h"
+#include "components/gcm_driver/pref_names.h"
+#include "components/pref_registry/pref_registry_syncable.h"
+#include "components/prefs/pref_service.h"
 #include "components/sync_driver/sync_util.h"
+#include "components/version_info/version_info.h"
 #include "url/gurl.h"
 
 namespace gcm {
@@ -63,11 +70,49 @@ std::string GetVersion() {
   return version_info::GetVersionNumber();
 }
 
-GCMClient::ChromeBuildInfo GetChromeBuildInfo(version_info::Channel channel) {
+std::string ToLowerAlphaNum(base::StringPiece in) {
+  std::string out;
+  out.reserve(in.size());
+  for (size_t i = 0; i < in.size(); i++) {
+    if (base::IsAsciiAlpha(in[i]) || base::IsAsciiDigit(in[i]))
+      out.push_back(base::ToLowerASCII(in[i]));
+  }
+  return out;
+}
+
+// Returns a string like "com.chrome.stable.macosx" that should be used as the
+// GCM category when an app_id is sent as a subtype instead of as a category.
+// This is generated once, then remains fixed forever (even if e.g. the product
+// name or channel change), since it must match existing Instance ID tokens.
+std::string CategoryForSubtypes(PrefService* prefs,
+                                const std::string& product_shortname,
+                                version_info::Channel channel_info) {
+  std::string category_for_subtypes =
+      prefs->GetString(prefs::kCategoryForSubtypes);
+  if (!category_for_subtypes.empty())
+    return category_for_subtypes;
+
+  std::string product = ToLowerAlphaNum(product_shortname);
+  std::string ns = product == "chromium" ? "org" : "com";

[Peter Beverloo, 2016/07/22 12:17:03]

This really feels like the wrong layer to make this decision, notably the fact
that it forces ".com" for non-Chromium builds :-(.

Have you considered moving this logic to
//chrome/browser/services/gcm/gcm_product_util.{cc,h} or similar, and just
passing in the |product_category| whenever constructing the GCM Driver?

[johnme, 2016/07/26 17:11:55]

Done.

+  std::string channel =
+      ToLowerAlphaNum(version_info::GetChannelString(channel_info));
+  std::string platform = ToLowerAlphaNum(version_info::GetOSType());
+  category_for_subtypes = ns + '.' + product + '.' + channel + '.' + platform;
+
+  prefs->SetString(prefs::kCategoryForSubtypes, category_for_subtypes);
+  return category_for_subtypes;
+}
+
+GCMClient::ChromeBuildInfo GetChromeBuildInfo(
+    PrefService* prefs,
+    const std::string& product_shortname,
+    version_info::Channel channel) {
   GCMClient::ChromeBuildInfo chrome_build_info;
   chrome_build_info.platform = GetPlatform();
   chrome_build_info.channel = GetChannel(channel);
   chrome_build_info.version = GetVersion();
+  chrome_build_info.category_for_subtypes =
+      CategoryForSubtypes(prefs, product_shortname, channel);
   return chrome_build_info;
 }
 
@@ -86,17 +131,24 @@ std::string GetUserAgent(version_info::Channel channel) {
 
 }  // namespace
 
+void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry) {
+  registry->RegisterStringPref(prefs::kCategoryForSubtypes,
+                               std::string() /* default_value */);
+}
+
 std::unique_ptr<GCMDriver> CreateGCMDriverDesktop(
     std::unique_ptr<GCMClientFactory> gcm_client_factory,
     PrefService* prefs,
     const base::FilePath& store_path,
     const scoped_refptr<net::URLRequestContextGetter>& request_context,
+    const std::string& product_shortname,
     version_info::Channel channel,
     const scoped_refptr<base::SequencedTaskRunner>& ui_task_runner,
     const scoped_refptr<base::SequencedTaskRunner>& io_task_runner,
     const scoped_refptr<base::SequencedTaskRunner>& blocking_task_runner) {
   return std::unique_ptr<GCMDriver>(new GCMDriverDesktop(
-      std::move(gcm_client_factory), GetChromeBuildInfo(channel),
+      std::move(gcm_client_factory),
+      GetChromeBuildInfo(prefs, product_shortname, channel),
       GetChannelStatusRequestUrl(channel), GetUserAgent(channel), prefs,
       store_path, request_context, ui_task_runner, io_task_runner,
       blocking_task_runner));