[mojo-edk] Prevent AcceptIncomingMessages flushing aggressively

mojo/edk/system/watch_unittest.cc

Index: mojo/edk/system/watch_unittest.cc
diff --git a/mojo/edk/system/watch_unittest.cc b/mojo/edk/system/watch_unittest.cc
index 7b3137f97c411d01d91f0f412b3a97d2ed33d2fc..ec28d94f8058f25d40abcb88bcebbc1161364bed 100644
--- a/mojo/edk/system/watch_unittest.cc
+++ b/mojo/edk/system/watch_unittest.cc
@@ -5,8 +5,11 @@
 #include <functional>
 
 #include "base/macros.h"
+#include "base/memory/ref_counted.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
+#include "base/single_thread_task_runner.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "mojo/edk/system/request_context.h"
 #include "mojo/edk/test/mojo_test_base.h"
 #include "mojo/public/c/system/functions.h"
@@ -29,7 +32,7 @@ class WatchHelper {
   using Callback =
       std::function<void(MojoResult result, MojoHandleSignalsState state)>;
 
-  WatchHelper() {}
+  WatchHelper() : task_runner_(base::ThreadTaskRunnerHandle::Get()) {}
   ~WatchHelper() {
     CHECK(!watching_);
   }
@@ -55,27 +58,32 @@ class WatchHelper {
     watching_ = false;
   }
 
-  void ExpectSystemNotifications() { expect_system_notifications_ = true; }
-
  private:
   static void OnNotify(uintptr_t context,
                        MojoResult result,
                        MojoHandleSignalsState state,
                        MojoWatchNotificationFlags flags) {
     WatchHelper* watcher = reinterpret_cast<WatchHelper*>(context);
+    watcher->task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&NotifyOnMainThread, context, result, state, flags));
+  }
+
+  static void NotifyOnMainThread(uintptr_t context,
+                                 MojoResult result,
+                                 MojoHandleSignalsState state,
+                                 MojoWatchNotificationFlags flags) {
+    WatchHelper* watcher = reinterpret_cast<WatchHelper*>(context);
     CHECK(watcher->watching_);
     if (result == MOJO_RESULT_CANCELLED)
       watcher->watching_ = false;
-    CHECK_EQ(flags, watcher->expect_system_notifications_?
-        MOJO_WATCH_NOTIFICATION_FLAG_FROM_SYSTEM :
-        MOJO_WATCH_NOTIFICATION_FLAG_NONE);
     watcher->callback_(result, state);
   }
 
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   bool watching_ = false;
   MojoHandle handle_;
   Callback callback_;
-  bool expect_system_notifications_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(WatchHelper);
 };
@@ -249,6 +257,7 @@ TEST_F(WatchTest, WatchWhileSatisfied) {
   WriteMessage(a, "hey");
   bool signaled = false;
   WatchHelper b_watcher;
+  base::RunLoop loop;
   b_watcher.Watch(
       b, MOJO_HANDLE_SIGNAL_READABLE,
       [&] (MojoResult result, MojoHandleSignalsState state) {
@@ -256,7 +265,9 @@ TEST_F(WatchTest, WatchWhileSatisfied) {
         EXPECT_EQ(MOJO_HANDLE_SIGNAL_READABLE,
                   state.satisfied_signals & MOJO_HANDLE_SIGNAL_READABLE);
         signaled = true;
+        loop.Quit();
       });
+  loop.Run();
   EXPECT_TRUE(signaled);
   b_watcher.Cancel();
 
@@ -419,6 +430,7 @@ TEST_F(WatchTest, NestedCancellation) {
   CreateMessagePipe(&a, &b);
   CreateMessagePipe(&c, &d);
 
+  base::RunLoop loop;
   bool a_watcher_run = false;
   WatchHelper a_watcher;
   a_watcher.Watch(
@@ -438,8 +450,9 @@ TEST_F(WatchTest, NestedCancellation) {
         // ...but this should prevent that notification from dispatching because
         // |a_watcher| is now cancelled.
         a_watcher.Cancel();
+
+        loop.Quit();
       });
-  c_watcher.ExpectSystemNotifications();
 
   {
     // Force "system" notifications for the synchronous behavior required to
@@ -451,6 +464,8 @@ TEST_F(WatchTest, NestedCancellation) {
     CloseHandle(d);
   }
 
+  loop.Run();
+
   EXPECT_FALSE(a_watcher.is_watching());
   EXPECT_FALSE(a_watcher_run);