Fix the handling of user gestures for external protocol handler dialogs.

chrome/browser/external_protocol/external_protocol_handler.cc

Index: chrome/browser/external_protocol/external_protocol_handler.cc
diff --git a/chrome/browser/external_protocol/external_protocol_handler.cc b/chrome/browser/external_protocol/external_protocol_handler.cc
index b414261cb32dd576f655e6e8529eba46d817e917..25ca460e5247f5ceb01838ba080bbc9322e1b688 100644
--- a/chrome/browser/external_protocol/external_protocol_handler.cc
+++ b/chrome/browser/external_protocol/external_protocol_handler.cc
@@ -27,10 +27,10 @@
 
 using content::BrowserThread;
 
-// Whether we accept requests for launching external protocols. This is set to
-// false every time an external protocol is requested, and set back to true on
-// each user gesture. This variable should only be accessed from the UI thread.
-static bool g_accept_requests = true;
+// Whether there is an existing user gesture. A user gesture is required to
+// launch external protocols. This variable should only be accessed from the UI
+// thread.
+static bool g_user_gesture = false;
 
 namespace {
 
@@ -204,8 +204,7 @@ void ExternalProtocolHandler::PrepopulateDictionary(
 // static
 ExternalProtocolHandler::BlockState ExternalProtocolHandler::GetBlockState(
     const std::string& scheme) {
-  // If we are being carpet bombed, block the request.
-  if (!g_accept_requests)
+  if (!g_user_gesture)
     return BLOCK;
 
   if (scheme.length() == 1) {
@@ -270,8 +269,6 @@ void ExternalProtocolHandler::LaunchUrlWithDelegate(const GURL& url,
     return;
   }
 
-  g_accept_requests = false;
-
   // The worker creates tasks with references to itself and puts them into
   // message loops. When no tasks are left it will delete the observer and
   // eventually be deleted itself.
@@ -310,7 +307,13 @@ void ExternalProtocolHandler::RegisterPrefs(PrefRegistrySimple* registry) {
 }
 
 // static
-void ExternalProtocolHandler::PermitLaunchUrl() {
-  DCHECK(base::MessageLoopForUI::IsCurrent());
-  g_accept_requests = true;
+void ExternalProtocolHandler::EnableUserGesture() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  g_user_gesture = true;
+}
+
+// static
+void ExternalProtocolHandler::DisableUserGesture() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  g_user_gesture = false;
 }