[Extensions] Cleanup unused fields on AsyncApiFunction

AsyncApiFunction should go away entirely. Clean up some low-hanging
fruit in unused fields.

This CL has no behavior change whatsoever.

Bug: 1450946
Change-Id: Ib4c1b0aff6c369fe5e1603d543a9d9a6eee4b115
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4583938
Commit-Queue: David Bertoni <dbertoni@chromium.org>
Auto-Submit: Devlin Cronin <rdevlin.cronin@chromium.org>
Reviewed-by: David Bertoni <dbertoni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1152845}

extensions/browser/api/async_api_function.cc

@@ -24,7 +24,7 @@ AsyncApiFunction::~AsyncApiFunction() = default;
 bool AsyncApiFunction::RunAsync() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
-  if (!PrePrepare() || !Prepare()) {
+  if (!Prepare()) {
     return false;
   }
   bool rv = work_task_runner_->PostTask(
@@ -33,17 +33,8 @@ bool AsyncApiFunction::RunAsync() {
   return true;
 }
 
-bool AsyncApiFunction::PrePrepare() {
-  return true;
-}
-
 void AsyncApiFunction::Work() {}
 
-void AsyncApiFunction::AsyncWorkStart() {
-  Work();
-  AsyncWorkCompleted();
-}
-
 // static
 bool AsyncApiFunction::ValidationFailure(AsyncApiFunction* function) {
   return false;
@@ -71,10 +62,6 @@ void AsyncApiFunction::SetResult(base::Value result) {
   results_->Append(std::move(result));
 }
 
-void AsyncApiFunction::SetResultList(base::Value::List results) {
-  results_ = std::move(results);
-}
-
 void AsyncApiFunction::SetError(const std::string& error) {
   error_ = error;
 }
@@ -85,7 +72,8 @@ const std::string& AsyncApiFunction::GetError() const {
 
 void AsyncApiFunction::WorkOnWorkThread() {
   DCHECK(work_task_runner_->RunsTasksInCurrentSequence());
-  AsyncWorkStart();
+  Work();
+  AsyncWorkCompleted();
 }
 
 void AsyncApiFunction::RespondOnUIThread() {

extensions/browser/api/async_api_function.h

@@ -14,15 +14,12 @@ namespace extensions {
 
 // AsyncApiFunction provides convenient thread management for APIs that need to
 // do essentially all their work on a thread other than the UI thread.
+// TODO(crbug.com/1450946): Remove this class entirely.
 class AsyncApiFunction : public ExtensionFunction {
  protected:
   AsyncApiFunction();
   ~AsyncApiFunction() override;
 
-  // Like Prepare(). A useful place to put common work in an ApiFunction
-  // superclass that multiple API functions want to share.
-  virtual bool PrePrepare();
-
   // Set up for work (e.g., validate arguments). Guaranteed to happen on UI
   // thread.
   virtual bool Prepare() = 0;
@@ -31,10 +28,6 @@ class AsyncApiFunction : public ExtensionFunction {
   // |work_task_runner_| if non-null; or on the IO thread otherwise.
   virtual void Work();
 
-  // Start the asynchronous work. Guraranteed to happen on work thread.
-  virtual void AsyncWorkStart();
-
-  // Respond. Guaranteed to happen on UI thread.
   virtual bool Respond() = 0;
 
   // ExtensionFunction:
@@ -44,23 +37,12 @@ class AsyncApiFunction : public ExtensionFunction {
   // ValidationFailure override to match RunAsync().
   static bool ValidationFailure(AsyncApiFunction* function);
 
-  scoped_refptr<base::SequencedTaskRunner> work_task_runner() const {
-    return work_task_runner_;
-  }
-  void set_work_task_runner(
-      scoped_refptr<base::SequencedTaskRunner> work_task_runner) {
-    work_task_runner_ = work_task_runner;
-  }
-
   // Notify AsyncIOApiFunction that the work is completed
   void AsyncWorkCompleted();
 
   // Sets a single Value as the results of the function.
   void SetResult(base::Value result);
 
-  // Sets multiple Values as the results of the function.
-  void SetResultList(base::Value::List results);
-
   void SetError(const std::string& error);
   const std::string& GetError() const override;