Open external application dialog should not show for Chrome.

chrome/browser/external_protocol/external_protocol_handler.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/external_protocol/external_protocol_handler.h"
 
 #include <set>
 
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/string_util.h"
 #include "base/threading/thread.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process_impl.h"
 #include "chrome/browser/platform_util.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/prefs/scoped_user_pref_update.h"
+#include "chrome/browser/shell_integration.h"
 #include "chrome/common/pref_names.h"
 #include "googleurl/src/gurl.h"
 #include "net/base/escape.h"
 
 // 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;
 
 // static
@@ skipping 90 matching lines @@
 
     if (state == UNKNOWN) {
       update_excluded_schemas->Remove(scheme, NULL);
     } else {
       update_excluded_schemas->SetBoolean(scheme,
                                           state == BLOCK ? true : false);
     }
   }
 }
 
+namespace {

[tony, 2011/08/30 17:51:26]

Nit: I would move this to the top of the file (above the other functions in the
file).

+
+// When we are about to launch a URL with the default OS level application,
+// we check if that external application will be us. If it is we just ignore
+// the request.
+class ExternalDefaultProtocolObserver
+    : public ShellIntegration::DefaultWebClientObserver {
+ public:
+  ExternalDefaultProtocolObserver(const GURL& escaped_url,
+                                  int render_process_host_id,
+                                  int tab_contents_id,
+                                  bool prompt_user)
+      : escaped_url_(escaped_url),
+        render_process_host_id_(render_process_host_id),
+        tab_contents_id_(tab_contents_id),
+        prompt_user_(prompt_user) {}
+
+  virtual void SetDefaultWebClientUIState(
+      ShellIntegration::DefaultWebClientUIState state) OVERRIDE {
+

[tony, 2011/08/30 17:51:26]

Can we DCHECK that we're on the right thread here?

+    // If we are still working out if we're the default, or we've found
+    // out we definately are the default, we end here.
+    if (state == ShellIntegration::STATE_PROCESSING ||
+        state == ShellIntegration::STATE_IS_DEFAULT) {
+      return;
+    }
+
+    // If we get here, either we are not the default or we cannot work out
+    // what the default is, so we proceed.
+    if (prompt_user_) {
+      // Ask the user if they want to allow the protocol. This will call
+      // LaunchUrlWithoutSecurityCheck if the user decides to accept the
+      // protocol.
+      ExternalProtocolHandler::RunExternalProtocolDialog(
+          escaped_url_, render_process_host_id_, tab_contents_id_);
+      return;
+    }
+
+    ExternalProtocolHandler::LaunchUrlWithoutSecurityCheck(escaped_url_);
+  }
+
+  virtual bool IsOwnedByWorker() OVERRIDE { return true; }
+
+ private:
+  GURL escaped_url_;
+  int render_process_host_id_;
+  int tab_contents_id_;
+  bool prompt_user_;
+};
+
+} // namespace
+
 // static
 void ExternalProtocolHandler::LaunchUrl(const GURL& url,
                                         int render_process_host_id,
                                         int tab_contents_id) {
   DCHECK_EQ(MessageLoop::TYPE_UI, MessageLoop::current()->type());
 
   // Escape the input scheme to be sure that the command does not
   // have parameters unexpected by the external program.
   std::string escaped_url_string = EscapeExternalHandlerValue(url.spec());
   GURL escaped_url(escaped_url_string);
   BlockState block_state = GetBlockState(escaped_url.scheme());
   if (block_state == BLOCK)
     return;
 
   g_accept_requests = false;
 
-  if (block_state == UNKNOWN) {
-    // Ask the user if they want to allow the protocol. This will call
-    // LaunchUrlWithoutSecurityCheck if the user decides to accept the protocol.
-    RunExternalProtocolDialog(escaped_url,
-                              render_process_host_id,
-                              tab_contents_id);
-    return;
-  }
-
-  LaunchUrlWithoutSecurityCheck(escaped_url);
+  // 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.
+  ExternalDefaultProtocolObserver* observer;
+  observer = new ExternalDefaultProtocolObserver(url, render_process_host_id,

[tony, 2011/08/30 17:51:26]

Nit: Maybe merge this with the previous line.

+      tab_contents_id, block_state == UNKNOWN);
+  scoped_refptr<ShellIntegration::DefaultProtocolClientWorker> worker;
+  worker = new ShellIntegration::DefaultProtocolClientWorker(observer,

[tony, 2011/08/30 17:51:26]

Nit: Ditto

+      escaped_url.scheme());
+  // Start the check process running. This will send tasks to the FILE thread
+  // and when the answer is known will send the result back to the observer on
+  // the UI thread.
+  worker->StartCheckIsDefault();
 }
 
 // static
 void ExternalProtocolHandler::LaunchUrlWithoutSecurityCheck(const GURL& url) {
 #if defined(OS_MACOSX)
   // This must run on the UI thread on OS X.
   platform_util::OpenExternal(url);
 #else
   // Otherwise put this work on the file thread. On Windows ShellExecute may
   // block for a significant amount of time, and it shouldn't hurt on Linux.
@@ skipping 10 matching lines @@
 // static
 void ExternalProtocolHandler::RegisterPrefs(PrefService* prefs) {
   prefs->RegisterDictionaryPref(prefs::kExcludedSchemes);
 }
 
 // static
 void ExternalProtocolHandler::PermitLaunchUrl() {
   DCHECK_EQ(MessageLoop::TYPE_UI, MessageLoop::current()->type());
   g_accept_requests = true;
 }