[RemotePlayback] Implement 'connecting' state

third_party/WebKit/Source/modules/remoteplayback/RemotePlayback.cpp

Index: third_party/WebKit/Source/modules/remoteplayback/RemotePlayback.cpp
diff --git a/third_party/WebKit/Source/modules/remoteplayback/RemotePlayback.cpp b/third_party/WebKit/Source/modules/remoteplayback/RemotePlayback.cpp
index 88530f205fd29c710f6d891543122b4dc6d3f546..86c69e2d965117b42174b68a91101bc8e12f2349 100644
--- a/third_party/WebKit/Source/modules/remoteplayback/RemotePlayback.cpp
+++ b/third_party/WebKit/Source/modules/remoteplayback/RemotePlayback.cpp
@@ -205,11 +205,9 @@ void RemotePlayback::notifyInitialAvailability(int callbackId) {
 }
 
 void RemotePlayback::stateChanged(WebRemotePlaybackState state) {
-  // We may get a "disconnected" state change while in the "disconnected"
-  // state if initiated connection fails. So cleanup the promise resolvers
-  // before checking if anything changed.
-  // TODO(avayvod): cleanup this logic when implementing the "connecting"
-  // state.
+  if (m_state == state)
+    return;
+
   if (m_promptPromiseResolver) {
     // Changing state to Disconnected from "disconnected" or "connecting" means
     // that establishing connection with remote playback device failed.
@@ -220,14 +218,15 @@ void RemotePlayback::stateChanged(WebRemotePlaybackState state) {
       m_promptPromiseResolver->reject(DOMException::create(
           AbortError, "Failed to connect to the remote device."));
     } else {
+      DCHECK((m_state == WebRemotePlaybackState::Disconnected &&
+              state == WebRemotePlaybackState::Connecting) ||
+             (m_state == WebRemotePlaybackState::Connected &&
+              state == WebRemotePlaybackState::Disconnected));
       m_promptPromiseResolver->resolve();
     }
     m_promptPromiseResolver = nullptr;
   }
 
-  if (m_state == state)
-    return;
-
   m_state = state;
   switch (m_state) {
     case WebRemotePlaybackState::Connecting: