Debugger: Cleanups and improvements for status notification.

Worker/Job:
- Add job listener hooks for when work actually begins for a job,
  and when a job is suspended to wait for user input.
- Add hook for setting a job description string, and implement in several
  subclasses.

LoadImageDebugInfoJob:
- Get rid of ImageDebugInfoJobListener since its functionality can be
  handled via the more general job wait for user input hook. Refactor
  accordingly.

TeamDebugger:
- Adjust to use new job hooks. When a worker job is initiated, we now
  check if the job has a description, and if so pass it on to the UI
  to display a notification.

DwarfLoadingStateHandler:
- Notify the UI when a package download is in progress.

With these changes, the status bar now notifies the user if any of the
following actions are in flight:

1) Loading/parsing debug information
2) Stack trace retrieval
3) Source code retrieval
4) Downloading a debug info package

src/apps/debugger/controllers/TeamDebugger.cpp

@@ -13,6 +13,7 @@
 #include <new>
 
 #include <Entry.h>
+#include <InterfaceDefs.h>
 #include <Message.h>
 #include <StringList.h>
 
@@ -1369,6 +1370,17 @@ TeamDebugger::UserInterfaceQuitRequested(QuitOption quitOption)
 }
 
 
+void
+TeamDebugger::JobStarted(Job* job)
+{
+	BString description(job->GetDescription());
+	if (!description.IsEmpty()) {
+		description.Append(B_UTF8_ELLIPSIS);
+		fUserInterface->NotifyBackgroundWorkStatus(description.String());
+	}
+}
+
+
 void
 TeamDebugger::JobDone(Job* job)
 {
@@ -1377,6 +1389,21 @@ TeamDebugger::JobDone(Job* job)
 }
 
 
+void
+TeamDebugger::JobWaitingForInput(Job* job)
+{
+	LoadImageDebugInfoJob* infoJob = dynamic_cast<LoadImageDebugInfoJob*>(job);
+
+	if (infoJob == NULL)
+		return;
+
+	BMessage message(MSG_DEBUG_INFO_NEEDS_USER_INPUT);
+	message.AddPointer("job", infoJob);
+	message.AddPointer("state", infoJob->GetLoadingState());
+	PostMessage(&message);
+}
+
+
 void
 TeamDebugger::JobFailed(Job* job)
 {
@@ -1396,30 +1423,6 @@ TeamDebugger::JobAborted(Job* job)
 }
 
 
-void
-TeamDebugger::ImageDebugInfoJobNeedsUserInput(Job* job,
-	ImageDebugInfoLoadingState* state)
-{
-	TRACE_JOBS("TeamDebugger::DebugInfoJobNeedsUserInput(%p, %p)\n",
-		job, state);
-
-	BMessage message(MSG_DEBUG_INFO_NEEDS_USER_INPUT);
-	message.AddPointer("job", job);
-	message.AddPointer("state", state);
-	PostMessage(&message);
-}
-
-
-void
-TeamDebugger::ImageDebugInfoJobInProgress(Image* image)
-{
-	BString message;
-	message.SetToFormat("Loading debug information for %s...",
-		image->Name().String());
-	fUserInterface->NotifyBackgroundWorkStatus(message.String());
-}
-
-
 void
 TeamDebugger::ThreadStateChanged(const ::Team::ThreadEvent& event)
 {