Add support for GCM subtypes to desktop Instance ID implementation

ios/chrome/browser/services/gcm/ios_chrome_gcm_profile_service_factory.cc

Index: ios/chrome/browser/services/gcm/ios_chrome_gcm_profile_service_factory.cc
diff --git a/ios/chrome/browser/services/gcm/ios_chrome_gcm_profile_service_factory.cc b/ios/chrome/browser/services/gcm/ios_chrome_gcm_profile_service_factory.cc
index abe148c203262355df0d8991b94d1f0454b14f48..35db7f15f76565e9b6cd4b45e050a9782448bdfc 100644
--- a/ios/chrome/browser/services/gcm/ios_chrome_gcm_profile_service_factory.cc
+++ b/ios/chrome/browser/services/gcm/ios_chrome_gcm_profile_service_factory.cc
@@ -32,6 +32,18 @@ IOSChromeGCMProfileServiceFactory::GetInstance() {
   return base::Singleton<IOSChromeGCMProfileServiceFactory>::get();
 }
 
+// static
+std::string IOSChromeGCMProfileServiceFactory::GetProductCategoryForSubtypes() {
+#if defined(GOOGLE_CHROME_BUILD)
+  std::string channel = ::GetChannelString();
+  if (channel.empty())
+    channel = "stable";
+  return "com.chrome." + channel + ".ios";
+#else
+  return "org.chromium.unknown.ios";
+#endif

[droger, 2016/08/16 08:05:23]

Why is this code different on iOS? Would it make sense to use the cross platform
code instead?

[johnme, 2016/08/18 17:43:22]

iOS can't access the cross platform version in
chrome/browser/services/gcm/gcm_product_util.h, and it doesn't make sense to
move that to components since it contains product-specific naming logic that
other embedders might wish to change (indeed a previous reviewer made me move it
from components/ to chrome/).

Rather than duplicating the complex logic (which would be especially tricky
since it depends on PRODUCT_SHORTNAME_STRING which doesn't seem to exist on
iOS), I was able to implement a simpler form for iOS that hardcodes the names
"chrome" or "chromium" depending on the GOOGLE_CHROME_BUILD (the same way iOS
defines kProductDirName).

[droger, 2016/08/19 09:10:28]

Ok thanks, this seems reasonable indeed.

FYI there is IDS_IOS_SHORT_PRODUCT_NAME on iOS which is probably equivalent to
PRODUCT_SHORTNAME_STRING.

+}
+
 IOSChromeGCMProfileServiceFactory::IOSChromeGCMProfileServiceFactory()
     : BrowserStateKeyedServiceFactory(
           "GCMProfileService",
@@ -57,6 +69,7 @@ IOSChromeGCMProfileServiceFactory::BuildServiceInstanceFor(
   return base::WrapUnique(new gcm::GCMProfileService(
       browser_state->GetPrefs(), browser_state->GetStatePath(),
       browser_state->GetRequestContext(), ::GetChannel(),
+      GetProductCategoryForSubtypes(),
       base::WrapUnique(new ProfileIdentityProvider(
           ios::SigninManagerFactory::GetForBrowserState(browser_state),
           OAuth2TokenServiceFactory::GetForBrowserState(browser_state),