Add a check to the registry before the intent infobar is shown.

chrome/browser/intents/register_intent_handler_infobar_delegate.cc

Index: chrome/browser/intents/register_intent_handler_infobar_delegate.cc
diff --git a/chrome/browser/intents/register_intent_handler_infobar_delegate.cc b/chrome/browser/intents/register_intent_handler_infobar_delegate.cc
index 4c711e4c95e4a25b67708cf772a0bb007062dca7..7c227ba158d59b45cc9c4ae4cc7f484a83ad6ad1 100644
--- a/chrome/browser/intents/register_intent_handler_infobar_delegate.cc
+++ b/chrome/browser/intents/register_intent_handler_infobar_delegate.cc
@@ -4,8 +4,11 @@
 
 #include "chrome/browser/intents/register_intent_handler_infobar_delegate.h"
 
+#include "base/bind.h"
+#include "base/bind_helpers.h"
 #include "base/logging.h"
 #include "base/utf_string_conversions.h"
+#include "chrome/browser/infobars/infobar_tab_helper.h"
 #include "chrome/browser/intents/web_intents_registry.h"
 #include "chrome/browser/intents/web_intents_registry_factory.h"
 #include "chrome/browser/profiles/profile.h"
@@ -60,3 +63,29 @@ bool RegisterIntentHandlerInfoBarDelegate::LinkClicked(
   // TODO(jhawkins): Add associated bug for the article here.
   return false;
 }
+
+// Helper continuation for MaybeShowIntentInfoBar.
+void CheckProvider(

[James Hawkins, 2011/10/26 23:50:06]

Move to an unnamed namespace.

[Greg Billock, 2011/10/29 00:03:19]

Done.

+    InfoBarTabHelper* infobar_helper,
+    WebIntentsRegistry* registry,

[James Hawkins, 2011/10/26 23:50:06]

Just an FYI: for implementation, parameters may be filled to 80 cols; the only
constraint is that each start of a line of parameters must line up on the same
column. This generally saves line space in the implementation.

[Greg Billock, 2011/10/29 00:03:19]

Moved these up and indented.

On 2011/10/26 23:50:06, James Hawkins wrote:

+    const WebIntentServiceData& service,
+    bool provider_exists) {
+  if (!provider_exists) {

[James Hawkins, 2011/10/26 23:50:06]

Perhaps this parameter could be removed and the continuation only called if it
does not exist?

[Greg Billock, 2011/10/29 00:03:19]

Hmmm. So the signature is something like NotifyIfIntentProviderDoesNotExist...
I'm not sure that's least surprising, although it's definitely nicer for this
case.

+    infobar_helper->AddInfoBar(new RegisterIntentHandlerInfoBarDelegate(
+        infobar_helper, registry, service));
+  }
+}
+
+// static
+void RegisterIntentHandlerInfoBarDelegate::MaybeShowIntentInfoBar(
+    InfoBarTabHelper* infobar_helper,
+    WebIntentsRegistry* registry,
+    const WebIntentServiceData& service) {
+  DCHECK(infobar_helper);
+  DCHECK(registry);
+  registry->IntentProviderExists(service,
+                                 base::Bind(&CheckProvider,
+                                            base::Unretained(infobar_helper),
+                                            base::Unretained(registry),
+                                            service));
+}