[CQ][PE] remove stale DisplayRefreshManager; attach cleanup (#8238)

With the removal of the Swing Performance tool window, the
`DisplayRefreshManager` was orphaned. Besides cleaning up unnecessary
code, removing it also addresses occasional user-facing errors
(#8148).

Also removes `attach` flag from `addRegisteredExtensionRPCs`, introduced
in #2920 but long
unused.

Fixes: #8148.



---

- [x] I’ve reviewed the contributor guide and applied the relevant
portions to this PR.

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  <summary>Contribution guidelines:</summary><br>

- See our [contributor
guide]([https://github.com/dart-lang/sdk/blob/main/CONTRIBUTING.md](https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview)
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Author: pq

flutter-idea/src/io/flutter/vmService/DisplayRefreshRateManager.java

@@ -53,16 +53,13 @@ public class VMServiceManager implements FlutterApp.FlutterAppListener, Disposab
 
   private final Set<String> registeredServices = new HashSet<>();
 
-  @NotNull public final DisplayRefreshRateManager displayRefreshRateManager;
-
   public VMServiceManager(@NotNull FlutterApp app, @NotNull VmService vmService) {
     this.app = app;
     this.vmService = vmService;
     app.addStateListener(this);
 
     assert (app.getFlutterDebugProcess() != null);
 
-    this.displayRefreshRateManager = new DisplayRefreshRateManager(this, vmService);
     flutterIsolateRefStream = new EventStream<>();
 
     // The VM Service depends on events from the Extension event stream to determine when Flutter.Frame
@@ -107,7 +104,7 @@ public void received(Isolate isolate) {
                   }
                 }
               }
-              addRegisteredExtensionRPCs(isolate, false);
+              addRegisteredExtensionRPCs(isolate);
             }
 
             @Override
@@ -125,7 +122,7 @@ public void onError(RPCError error) {
     setServiceExtensionState(enableOnDeviceInspector.getExtension(), true, true);
   }
 
-  public void addRegisteredExtensionRPCs(Isolate isolate, boolean attach) {
+  public void addRegisteredExtensionRPCs(Isolate isolate) {
     if (isolate.getExtensionRPCs() != null) {
       for (String extension : isolate.getExtensionRPCs()) {
         addServiceExtension(extension);
@@ -278,9 +275,6 @@ private void onFrameEventReceived() {
         addServiceExtension(extensionName);
       }
       pendingServiceExtensions.clear();
-
-      // Query for display refresh rate and add the value to the stream.
-      displayRefreshRateManager.queryRefreshRate();
     }
   }
 

flutter-idea/src/io/flutter/vmService/VMServiceManager.java

@@ -338,7 +338,7 @@ private void setInitialBreakpointsAndCheckExtensions(@NotNull IsolateRef isolate
     if (app != null) {
       VMServiceManager service = app.getVMServiceManager();
       if (service != null) {
-        service.addRegisteredExtensionRPCs(isolate, true);
+        service.addRegisteredExtensionRPCs(isolate);
       }
     }
   }