Wait for the Dart plugin to start the DevTools server with retries (#8177)

Fixes #8144

This PR:
* Makes sure we only ever have one connected DevTools server
* Tracks the start-up of the DevTools server using the [Progress API](https://plugins.jetbrains.com/docs/intellij/background-processes.html) instead of `executeOnPooledThread` (logic pulled into `DevToolsServerTask.java`). This allows us to display the progress and cancel the server startup on `forceRestart`.
* Retries waiting for the Dart plugin initiated DevTools server until a timeout is reached
* If the Dart plugin DevTools is not ready by the timeout, switching to a new Flutter panel will re-trigger starting the server

### Server start-up status:
<img width="466" alt="Screenshot 2025-05-09 at 12 40 31 PM" src="https://github.com/user-attachments/assets/8f9d7579-426d-4ef9-8f85-bc0789320d52" />

### Message if waiting for the server timed out:
<img width="501" alt="Screenshot 2025-05-09 at 1 26 55 PM" src="https://github.com/user-attachments/assets/25ef03e6-6d5e-44ee-9c29-5276912b3427" />

### Loaded Property Editor:
<img width="904" alt="Screenshot 2025-05-09 at 12 39 37 PM" src="https://github.com/user-attachments/assets/f538f835-2015-4289-ade4-76514088575c" />

Author: elliette

flutter-idea/src/io/flutter/devtools/AbstractDevToolsViewFactory.java

@@ -6,8 +6,11 @@
 package io.flutter.devtools;
 
 import com.intellij.openapi.project.Project;
+import com.intellij.openapi.util.Disposer;
 import com.intellij.openapi.wm.ToolWindow;
 import com.intellij.openapi.wm.ToolWindowFactory;
+import com.intellij.openapi.wm.ex.ToolWindowManagerListener;
+import com.intellij.util.messages.MessageBusConnection;
 import io.flutter.FlutterUtils;
 import io.flutter.actions.RefreshToolWindowAction;
 import io.flutter.run.daemon.DevToolsInstance;
@@ -42,7 +45,10 @@ public abstract DevToolsUrl getDevToolsUrl(@NotNull Project project,
                                              @NotNull FlutterSdkVersion flutterSdkVersion,
                                              @NotNull DevToolsInstance instance);
 
-  protected void doAfterBrowserOpened(@NotNull Project project, @NotNull EmbeddedBrowser browser) {}
+  protected void doAfterBrowserOpened(@NotNull Project project, @NotNull EmbeddedBrowser browser) {
+  }
+
+  private boolean devToolsLoadedInBrowser = false;
 
   @Override
   public Object isApplicableAsync(@NotNull Project project, @NotNull Continuation<? super Boolean> $completion) {
@@ -98,19 +104,36 @@ public void createToolWindowContent(@NotNull Project project, @NotNull ToolWindo
     }
 
     // Final case:
+    loadDevToolsInEmbeddedBrowser(project, toolWindow, flutterSdkVersion);
+
+    // Finally, listen for the panel to be reopened and potentially reload DevTools.
+    maybeReloadDevToolsWhenVisible(project, toolWindow, flutterSdkVersion);
+  }
+
+  private void loadDevToolsInEmbeddedBrowser(@NotNull Project project,
+                                             @NotNull ToolWindow toolWindow,
+                                             @NotNull FlutterSdkVersion flutterSdkVersion) {
+    viewUtils.presentLabel(toolWindow, "Loading " + getToolWindowTitle() + "...");
+
     AsyncUtils.whenCompleteUiThread(
       DevToolsService.getInstance(project).getDevToolsInstance(),
       (instance, error) -> {
         // Skip displaying if the project has been closed.
         if (!project.isOpen()) {
+          viewUtils.presentLabel(toolWindow, "Project is closed.");
           return;
         }
 
+        // Show a message if DevTools started with an error.
+        final String restartDevToolsMessage = "Try switching to another Flutter panel and back again to restart the server.";
         if (error != null) {
+          viewUtils.presentLabels(toolWindow, List.of("Flutter DevTools start-up failed.", restartDevToolsMessage));
           return;
         }
 
+        // Show a message if there is no DevTools yet.
         if (instance == null) {
+          viewUtils.presentLabels(toolWindow, List.of("Flutter DevTools does not exist.", restartDevToolsMessage));
           return;
         }
 
@@ -122,14 +145,30 @@ public void createToolWindowContent(@NotNull Project project, @NotNull ToolWindo
             .ifPresent(embeddedBrowser ->
                        {
                          embeddedBrowser.openPanel(toolWindow, getToolWindowTitle(), devToolsUrl, System.out::println);
+                         devToolsLoadedInBrowser = true;
                          doAfterBrowserOpened(project, embeddedBrowser);
+                         // The "refresh" action refreshes the embedded browser, not the panel.
+                         // Therefore, we only show it once we have an embedded browser.
+                         toolWindow.setTitleActions(List.of(new RefreshToolWindowAction(getToolWindowId())));
                        });
         });
       }
     );
+  }
 
-    // TODO(helin24): It may be better to add this to the gear actions or to attach as a mouse event on individual tabs within a tool
-    //  window, but I wasn't able to get either working immediately.
-    toolWindow.setTitleActions(List.of(new RefreshToolWindowAction(getToolWindowId())));
+  private void maybeReloadDevToolsWhenVisible(@NotNull Project project,
+                                              @NotNull ToolWindow toolWindow, @NotNull FlutterSdkVersion flutterSdkVersion) {
+    MessageBusConnection connection = project.getMessageBus().connect();
+    connection.subscribe(ToolWindowManagerListener.TOPIC, new ToolWindowManagerListener() {
+      @Override
+      public void toolWindowShown(@NotNull ToolWindow activatedToolWindow) {
+        if (activatedToolWindow.getId().equals(getToolWindowId())) {
+          if (!devToolsLoadedInBrowser) {
+            loadDevToolsInEmbeddedBrowser(project, toolWindow, flutterSdkVersion);
+          }
+        }
+      }
+    });
+    Disposer.register(toolWindow.getDisposable(), connection);
   }
-}
+}