MSE-in-Workers: Rename MediaSourceTracerImpl

Like the recent rename of MediaSourceAttachmentImpl to
SameThreadMediaSourceAttachment [1], this change renames
MediaSourceTracerImpl to SameThreadMediaSourceTracer. There is no
behavior change.

This change makes it more clear that the tracer being renamed here is
the same-thread version, since later changes will introduce a
cross-thread version.

[1] https://crrev.com/803635

BUG=878133

Change-Id: I3cfa000db21ca87fe79bf73ea2d2490c1976df32
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2390966Reviewed-by: Will Cassella <cassew@google.com>
Commit-Queue: Matthew Wolenetz <wolenetz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#804446}

third_party/blink/renderer/modules/mediasource/BUILD.gn

@@ -14,10 +14,10 @@ blink_modules_sources("mediasource") {
     "media_source_attachment_supplement.h",
     "media_source_registry_impl.cc",
     "media_source_registry_impl.h",
-    "media_source_tracer_impl.cc",
-    "media_source_tracer_impl.h",
     "same_thread_media_source_attachment.cc",
     "same_thread_media_source_attachment.h",
+    "same_thread_media_source_tracer.cc",
+    "same_thread_media_source_tracer.h",
     "source_buffer.cc",
     "source_buffer.h",
     "source_buffer_list.cc",

third_party/blink/renderer/modules/mediasource/media_source.cc

@@ -20,7 +20,7 @@
 #include "third_party/blink/renderer/core/html/media/html_media_element.h"
 #include "third_party/blink/renderer/core/html/track/audio_track_list.h"
 #include "third_party/blink/renderer/core/html/track/video_track_list.h"
-#include "third_party/blink/renderer/modules/mediasource/media_source_tracer_impl.h"
+#include "third_party/blink/renderer/modules/mediasource/same_thread_media_source_tracer.h"
 #include "third_party/blink/renderer/modules/mediasource/source_buffer_track_base_supplement.h"
 #include "third_party/blink/renderer/platform/bindings/exception_messages.h"
 #include "third_party/blink/renderer/platform/bindings/exception_state.h"
@@ -855,7 +855,7 @@ MediaSourceTracer* MediaSource::StartAttachingToMediaElement(
   attached_element_ = element;
   media_source_attachment_ = attachment;
   attachment_tracer_ =
-      MakeGarbageCollected<MediaSourceTracerImpl>(element, this);
+      MakeGarbageCollected<SameThreadMediaSourceTracer>(element, this);
   return attachment_tracer_;
 }
 

third_party/blink/renderer/modules/mediasource/media_source_attachment_supplement.cc

@@ -5,7 +5,7 @@
 #include "third_party/blink/renderer/modules/mediasource/media_source_attachment_supplement.h"
 
 #include "third_party/blink/renderer/modules/mediasource/media_source.h"
-#include "third_party/blink/renderer/modules/mediasource/media_source_tracer_impl.h"
+#include "third_party/blink/renderer/modules/mediasource/same_thread_media_source_tracer.h"
 
 namespace blink {
 

third_party/blink/renderer/modules/mediasource/same_thread_media_source_attachment.cc

@@ -7,15 +7,16 @@
 #include "base/memory/scoped_refptr.h"
 #include "third_party/blink/renderer/core/html/media/html_media_element.h"
 #include "third_party/blink/renderer/modules/mediasource/media_source.h"
-#include "third_party/blink/renderer/modules/mediasource/media_source_tracer_impl.h"
+#include "third_party/blink/renderer/modules/mediasource/same_thread_media_source_tracer.h"
 
 namespace {
 // Downcasts |tracer| to the expected same-thread attachment's tracer type.
 // Includes a debug-mode check that the tracer matches the expected attachment
 // semantic.
-blink::MediaSourceTracerImpl* GetTracerImpl(blink::MediaSourceTracer* tracer) {
+blink::SameThreadMediaSourceTracer* GetTracerImpl(
+    blink::MediaSourceTracer* tracer) {
   DCHECK(!tracer || !tracer->IsCrossThreadForDebugging());
-  return static_cast<blink::MediaSourceTracerImpl*>(tracer);
+  return static_cast<blink::SameThreadMediaSourceTracer*>(tracer);
 }
 
 blink::MediaSource* GetMediaSource(blink::MediaSourceTracer* tracer) {

third_party/blink/renderer/modules/mediasource/media_source_tracer_impl.cc → third_party/blink/renderer/modules/mediasource/same_thread_media_source_tracer.cc

@@ -2,18 +2,19 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "third_party/blink/renderer/modules/mediasource/media_source_tracer_impl.h"
+#include "third_party/blink/renderer/modules/mediasource/same_thread_media_source_tracer.h"
 
 #include "third_party/blink/renderer/core/html/media/html_media_element.h"
 #include "third_party/blink/renderer/modules/mediasource/media_source.h"
 
 namespace blink {
 
-MediaSourceTracerImpl::MediaSourceTracerImpl(HTMLMediaElement* media_element,
-                                             MediaSource* media_source)
+SameThreadMediaSourceTracer::SameThreadMediaSourceTracer(
+    HTMLMediaElement* media_element,
+    MediaSource* media_source)
     : media_element_(media_element), media_source_(media_source) {}
 
-void MediaSourceTracerImpl::Trace(Visitor* visitor) const {
+void SameThreadMediaSourceTracer::Trace(Visitor* visitor) const {
   visitor->Trace(media_element_);
   visitor->Trace(media_source_);
   MediaSourceTracer::Trace(visitor);

third_party/blink/renderer/modules/mediasource/media_source_tracer_impl.h → third_party/blink/renderer/modules/mediasource/same_thread_media_source_tracer.h

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef THIRD_PARTY_BLINK_RENDERER_MODULES_MEDIASOURCE_MEDIA_SOURCE_TRACER_IMPL_H_
-#define THIRD_PARTY_BLINK_RENDERER_MODULES_MEDIASOURCE_MEDIA_SOURCE_TRACER_IMPL_H_
+#ifndef THIRD_PARTY_BLINK_RENDERER_MODULES_MEDIASOURCE_SAME_THREAD_MEDIA_SOURCE_TRACER_H_
+#define THIRD_PARTY_BLINK_RENDERER_MODULES_MEDIASOURCE_SAME_THREAD_MEDIA_SOURCE_TRACER_H_
 
 #include "third_party/blink/renderer/core/html/media/media_source_tracer.h"
 #include "third_party/blink/renderer/platform/heap/handle.h"
@@ -17,13 +17,13 @@ class MediaSource;
 // MediaSource on the same (main) thread to trace into each other. This enables
 // garbage collection to automatically detect and collect idle attachments of
 // these objects that have no other strong references. Concrete
-// MediaSourceAttachments use MediaSourceTracerImpls as the authoritative
+// MediaSourceAttachments use SameThreadMediaSourceTracers as the authoritative
 // reference holders for each side of the attachments.
-class MediaSourceTracerImpl final : public MediaSourceTracer {
+class SameThreadMediaSourceTracer final : public MediaSourceTracer {
  public:
-  MediaSourceTracerImpl(HTMLMediaElement* media_element,
-                        MediaSource* media_source);
-  ~MediaSourceTracerImpl() override = default;
+  SameThreadMediaSourceTracer(HTMLMediaElement* media_element,
+                              MediaSource* media_source);
+  ~SameThreadMediaSourceTracer() override = default;
 
   void Trace(Visitor* visitor) const override;
 
@@ -40,4 +40,4 @@ class MediaSourceTracerImpl final : public MediaSourceTracer {
 
 }  // namespace blink
 
-#endif  // THIRD_PARTY_BLINK_RENDERER_MODULES_MEDIASOURCE_MEDIA_SOURCE_TRACER_IMPL_H_
+#endif  // THIRD_PARTY_BLINK_RENDERER_MODULES_MEDIASOURCE_SAME_THREAD_MEDIA_SOURCE_TRACER_H_