Fix g_k_* symbols after blink rename.

third_party/WebKit/Source/modules/mediasource/SourceBufferTrackBaseSupplement.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/mediasource/SourceBufferTrackBaseSupplement.h"
 
 #include "core/html/track/TrackBase.h"
 #include "modules/mediasource/SourceBuffer.h"
 
 namespace blink {
 
-static const char* g_k_supplement_name = "SourceBufferTrackBaseSupplement";
+static const char kSupplementName[] = "SourceBufferTrackBaseSupplement";
 
 // static
 SourceBufferTrackBaseSupplement* SourceBufferTrackBaseSupplement::FromIfExists(
     TrackBase& track) {
   return static_cast<SourceBufferTrackBaseSupplement*>(
-      Supplement<TrackBase>::From(track, g_k_supplement_name));
+      Supplement<TrackBase>::From(track, kSupplementName));
 }
 
 // static
 SourceBufferTrackBaseSupplement& SourceBufferTrackBaseSupplement::From(
     TrackBase& track) {
   SourceBufferTrackBaseSupplement* supplement = FromIfExists(track);
   if (!supplement) {
     supplement = new SourceBufferTrackBaseSupplement();
-    Supplement<TrackBase>::ProvideTo(track, g_k_supplement_name, supplement);
+    Supplement<TrackBase>::ProvideTo(track, kSupplementName, supplement);
   }
   return *supplement;
 }
 
 // static
 SourceBuffer* SourceBufferTrackBaseSupplement::sourceBuffer(TrackBase& track) {
   SourceBufferTrackBaseSupplement* supplement = FromIfExists(track);
   if (supplement)
     return supplement->source_buffer_;
   return nullptr;
 }
 
 void SourceBufferTrackBaseSupplement::SetSourceBuffer(
     TrackBase& track,
     SourceBuffer* source_buffer) {
   From(track).source_buffer_ = source_buffer;
 }
 
 DEFINE_TRACE(SourceBufferTrackBaseSupplement) {
   visitor->Trace(source_buffer_);
   Supplement<TrackBase>::Trace(visitor);
 }
 
 }  // namespace blink