[wasm] Remove unused compilation event.

R=ahaas@chromium.org

Change-Id: I92d6e7fc41c9cbb3792a66c9ea8996efe1c8d87d
Reviewed-on: https://chromium-review.googlesource.com/1183434Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55276}

src/wasm/module-compiler.cc

@@ -52,8 +52,7 @@ namespace wasm {
 enum class CompilationEvent : uint8_t {
   kFinishedBaselineCompilation,
   kFinishedTopTierCompilation,
-  kFailedCompilation,
-  kDestroyed
+  kFailedCompilation
 };
 
 enum class CompileMode : uint8_t { kRegular, kTiering };
@@ -2466,9 +2465,6 @@ class AsyncCompileJob::PrepareAndStartCompile : public CompileStep {
                 job->DoSync<CompileFailed>(error);
                 return;
               }
-              case CompilationEvent::kDestroyed:
-                // Nothing to do.
-                return;
             }
             UNREACHABLE();
           });
@@ -2756,7 +2752,6 @@ CompilationState::CompilationState(internal::Isolate* isolate,
 CompilationState::~CompilationState() {
   background_task_manager_.CancelAndWait();
   foreground_task_manager_.CancelAndWait();
-  NotifyOnEvent(CompilationEvent::kDestroyed, nullptr);
 }
 
 void CompilationState::SetNumberOfFunctionsToCompile(size_t num_functions) {