[M70]Fix audio::InputIPC crash.

StreamCreated() may be called after CloseStream(), leading to a null
pointer deref on |delegate_|. Avoid this by invalidating the
weak pointer that was bound into StreamCreated().

Bug: 879257
Change-Id: I954421b384928bff3c3d17506850012e2a1da1b3
Reviewed-on: https://chromium-review.googlesource.com/1199142
Commit-Queue: Olga Sharonova <olka@chromium.org>
Reviewed-by: Olga Sharonova <olka@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#587981}(cherry picked from commit 4ef85aa)
Reviewed-on: https://chromium-review.googlesource.com/1202042
Reviewed-by: Max Morin <maxmorin@chromium.org>
Cr-Commit-Position: refs/branch-heads/3538@{#13}
Cr-Branched-From: 79f7c91-refs/heads/master@{#587811}

services/audio/public/cpp/input_ipc.cc

@@ -120,6 +120,9 @@ void InputIPC::CloseStream() {
   if (stream_client_binding_.is_bound())
     stream_client_binding_.Close();
   stream_.reset();
+
+  // Make sure we don't get any stale stream creation messages.
+  weak_factory_.InvalidateWeakPtrs();
 }
 
 void InputIPC::OnError() {

services/audio/public/cpp/input_ipc_unittest.cc

@@ -151,6 +151,13 @@ TEST_F(InputIPCTest, CreateStreamPropagates) {
   scoped_task_environment.RunUntilIdle();
 }
 
+TEST_F(InputIPCTest, StreamCreatedAfterCloseIsIgnored) {
+  StrictMock<MockDelegate> delegate;
+  ipc->CreateStream(&delegate, audioParameters, false, 0);
+  ipc->CloseStream();
+  scoped_task_environment.RunUntilIdle();
+}
+
 TEST_F(InputIPCTest, CreateStreamPropagatesInitiallyMuted) {
   StrictMock<MockDelegate> delegate;