chore: cherry-pick 913247c378d5 from chromium

patches/chromium/.patches

@@ -100,3 +100,4 @@ move_readablestream_requests_onto_the_stack_before_iteration.patch
 streams_convert_state_dchecks_to_checks.patch
 audiocontext_haspendingactivity_unless_it_s_closed.patch
 protect_automatic_pull_handlers_with_mutex.patch
+cherry-pick-913247c378d5.patch

patches/chromium/cherry-pick-913247c378d5.patch

@@ -0,0 +1,61 @@
+From 913247c378d54e0378ffd09524e0aa7503035fc4 Mon Sep 17 00:00:00 2001
+From: Hongchan Choi <hongchan@chromium.org>
+Date: Wed, 4 Mar 2020 00:45:41 +0000
+Subject: [PATCH] Use SupportsWeakPtr for messaging from rendering thread to
+ main thread
+
+In cross-thread messaging, the associated execution context can be
+already gone when a posted task is performed sometime later in the task
+runner's queue.
+
+By using WeakPtr, the task runner will not perform a scheduled task
+in the queue when the target object is invalid.
+
+Test: Locally confirmed that the repro does not crash.
+Bug: 1057627
+Change-Id: I51737594c918f6a4924c9a7ffe30db3e8de9a683
+Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2082897
+Commit-Queue: Hongchan Choi <hongchan@chromium.org>
+Reviewed-by: Raymond Toy <rtoy@chromium.org>
+Cr-Commit-Position: refs/heads/master@{#746613}
+---
+ .../renderer/modules/webaudio/audio_scheduled_source_node.cc | 2 +-
+ .../renderer/modules/webaudio/audio_scheduled_source_node.h  | 5 ++++-
+ 2 files changed, 5 insertions(+), 2 deletions(-)
+
+diff --git a/third_party/blink/renderer/modules/webaudio/audio_scheduled_source_node.cc b/third_party/blink/renderer/modules/webaudio/audio_scheduled_source_node.cc
+index 9594f5fe1c278..8e9c4c60163e0 100644
+--- a/third_party/blink/renderer/modules/webaudio/audio_scheduled_source_node.cc
++++ b/third_party/blink/renderer/modules/webaudio/audio_scheduled_source_node.cc
+@@ -250,7 +250,7 @@ void AudioScheduledSourceHandler::Finish() {
+   PostCrossThreadTask(
+       *task_runner_, FROM_HERE,
+       CrossThreadBindOnce(&AudioScheduledSourceHandler::NotifyEnded,
+-                          WrapRefCounted(this)));
++                          AsWeakPtr()));
+ }
+
+ void AudioScheduledSourceHandler::NotifyEnded() {
+diff --git a/third_party/blink/renderer/modules/webaudio/audio_scheduled_source_node.h b/third_party/blink/renderer/modules/webaudio/audio_scheduled_source_node.h
+index 2bf257ceabb3e..3cd126a3333d7 100644
+--- a/third_party/blink/renderer/modules/webaudio/audio_scheduled_source_node.h
++++ b/third_party/blink/renderer/modules/webaudio/audio_scheduled_source_node.h
+@@ -30,6 +30,7 @@
+ #define THIRD_PARTY_BLINK_RENDERER_MODULES_WEBAUDIO_AUDIO_SCHEDULED_SOURCE_NODE_H_
+
+ #include <atomic>
++#include "base/memory/weak_ptr.h"
+ #include "third_party/blink/renderer/bindings/core/v8/active_script_wrappable.h"
+ #include "third_party/blink/renderer/modules/webaudio/audio_node.h"
+
+@@ -38,7 +39,9 @@ namespace blink {
+ class BaseAudioContext;
+ class AudioBus;
+
+-class AudioScheduledSourceHandler : public AudioHandler {
++class AudioScheduledSourceHandler
++    : public AudioHandler,
++      public base::SupportsWeakPtr<AudioScheduledSourceHandler> {
+  public:
+   // These are the possible states an AudioScheduledSourceNode can be in:
+   //