message-pump: Change how MessagePumpDispatchers process events.

This patch allows a MessagePumpDispatcher to invoke the default handling of the message
in the message-pump by setting the DISPATCH_DEFAULT flag on the return value from the
::Dispatch() callback. As before, the dispatcher can still request a termination of the
current message-loop, but setting the DISPATCH_QUIT flag on the return value (instead of
returning false). The callback can set both flags, in which case the message-loop will
perform the default action, and also terminate the current loop.

As a result of this, we can remove duplicate code, namely aura::DispatcherWin, and
aura::Env::GetDispatcher(), that performs the same action as the default message pump.

R=darin@chromium.org, sky@chromium.org

Review URL: https://codereview.chromium.org/152083004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249860 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 5 insertions, 6 deletions

diff --git a/cloud_print/service/win/cloud_print_service_config.cc b/cloud_print/service/win/cloud_print_service_config.cc
index 58fcacc..9556826 100644
--- a/cloud_print/service/win/cloud_print_service_config.cc
+++ b/cloud_print/service/win/cloud_print_service_config.cc
@@ -37,13 +37,12 @@ class SetupDialog : public base::RefCounted<SetupDialog>,
     virtual ~Dispatcher() {};
 
     // MessagePumpDispatcher:
-    virtual bool Dispatch(const MSG& msg) OVERRIDE {
+    virtual uint32_t Dispatch(const MSG& msg) OVERRIDE {
       MSG msg2 = msg;
-      if (!dialog_->IsDialogMessage(&msg2)) {
-        ::TranslateMessage(&msg);
-        ::DispatchMessage(&msg);
-      }
-      return true;
+      uint32_t action = POST_DISPATCH_NONE;
+      if (!dialog_->IsDialogMessage(&msg2))
+        action = POST_DISPATCH_PERFORM_DEFAULT;
+      return action;
     }
 
    private: