Try to make PipeWire test more reliable

It appears to be still failing occasionally so add one more event
to verify streams connected successfully in order to verify whether
we sent and received buffers properly in the next step.

Bug: webrtc:14644
Change-Id: I08822b15452fc845d68cbff1b01ae6b6f7c1f486
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/282842
Reviewed-by: Alexander Cooper <alcooper@chromium.org>
Reviewed-by: Jeremy Leconte <jleconte@google.com>
Commit-Queue: Jan Grulich <grulja@gmail.com>
Cr-Commit-Position: refs/heads/main@{#38598}

modules/desktop_capture/linux/wayland/shared_screencast_stream.cc

@@ -224,6 +224,10 @@ void SharedScreenCastStreamPrivate::OnStreamStateChanged(
       RTC_LOG(LS_ERROR) << "PipeWire stream state error: " << error_message;
       break;
     case PW_STREAM_STATE_PAUSED:
+      if (that->observer_ && old_state != PW_STREAM_STATE_STREAMING) {
+        that->observer_->OnStreamConfigured();
+      }
+      break;
     case PW_STREAM_STATE_STREAMING:
     case PW_STREAM_STATE_UNCONNECTED:
     case PW_STREAM_STATE_CONNECTING:

modules/desktop_capture/linux/wayland/shared_screencast_stream.h

@@ -34,6 +34,7 @@ class RTC_EXPORT SharedScreenCastStream
     virtual void OnCursorShapeChanged() = 0;
     virtual void OnDesktopFrameChanged() = 0;
     virtual void OnFailedToProcessBuffer() = 0;
+    virtual void OnStreamConfigured() = 0;
 
    protected:
     Observer() = default;

modules/desktop_capture/linux/wayland/shared_screencast_stream_unittest.cc

@@ -23,6 +23,7 @@
 #include "test/gtest.h"
 
 using ::testing::_;
+using ::testing::AtLeast;
 using ::testing::Ge;
 using ::testing::Invoke;
 
@@ -39,16 +40,8 @@ class PipeWireStreamTest : public ::testing::Test,
                            public TestScreenCastStreamProvider::Observer,
                            public SharedScreenCastStream::Observer {
  public:
-  PipeWireStreamTest()
+  PipeWireStreamTest() = default;
-      : test_screencast_stream_provider_(
+  ~PipeWireStreamTest() = default;
-            std::make_unique<TestScreenCastStreamProvider>(this,
-                                                           kWidth,
-                                                           kHeight)) {
-    shared_screencast_stream_ = SharedScreenCastStream::CreateDefault();
-    shared_screencast_stream_->SetObserver(this);
-  }
-
-  ~PipeWireStreamTest() override {}
 
   // FakeScreenCastPortal::Observer
   MOCK_METHOD(void, OnBufferAdded, (), (override));
@@ -62,6 +55,14 @@ class PipeWireStreamTest : public ::testing::Test,
   MOCK_METHOD(void, OnCursorShapeChanged, (), (override));
   MOCK_METHOD(void, OnDesktopFrameChanged, (), (override));
   MOCK_METHOD(void, OnFailedToProcessBuffer, (), (override));
+  MOCK_METHOD(void, OnStreamConfigured, (), (override));
+
+  void SetUp() override {
+    shared_screencast_stream_ = SharedScreenCastStream::CreateDefault();
+    shared_screencast_stream_->SetObserver(this);
+    test_screencast_stream_provider_ =
+        std::make_unique<TestScreenCastStreamProvider>(this, kWidth, kHeight);
+  }
 
   void StartScreenCastStream(uint32_t stream_node_id) {
     shared_screencast_stream_->StartScreenCastStream(stream_node_id);
@@ -78,23 +79,24 @@ class PipeWireStreamTest : public ::testing::Test,
 TEST_F(PipeWireStreamTest, TestPipeWire) {
   // Set expectations for PipeWire to successfully connect both streams
   rtc::Event waitConnectEvent;
-  rtc::Event waitAddBufferEvent;
+  rtc::Event waitStartStreamingEvent;
 
   EXPECT_CALL(*this, OnStreamReady(_))
       .WillOnce(Invoke(this, &PipeWireStreamTest::StartScreenCastStream));
-  EXPECT_CALL(*this, OnStartStreaming).WillOnce([&waitConnectEvent] {
+  EXPECT_CALL(*this, OnStreamConfigured).WillOnce([&waitConnectEvent] {
     waitConnectEvent.Set();
   });
-  EXPECT_CALL(*this, OnBufferAdded).WillRepeatedly([&waitAddBufferEvent] {
+  EXPECT_CALL(*this, OnBufferAdded).Times(AtLeast(3));
-    waitAddBufferEvent.Set();
+  EXPECT_CALL(*this, OnStartStreaming).WillOnce([&waitStartStreamingEvent] {
+    waitStartStreamingEvent.Set();
   });
 
   // Give it some time to connect, the order between these shouldn't matter, but
   // we need to be sure we are connected before we proceed to work with frames.
   waitConnectEvent.Wait(kLongWait);
 
-  // Wait for an empty buffer to be added
+  // Wait until we start streaming
-  waitAddBufferEvent.Wait(kShortWait);
+  waitStartStreamingEvent.Wait(kShortWait);
 
   rtc::Event frameRetrievedEvent;
   EXPECT_CALL(*this, OnFrameRecorded).Times(3);