Introduce CancelUponDeferral() to buffered media loaders.

media/blink/run_all_unittests.cc

Index: media/blink/run_all_unittests.cc
diff --git a/media/blink/run_all_unittests.cc b/media/blink/run_all_unittests.cc
index 62b7120ae6b7afa175497d4d5c712c88cbe32aa5..7608420dea0a152dbf339db7b51d9712d1e73bbc 100644
--- a/media/blink/run_all_unittests.cc
+++ b/media/blink/run_all_unittests.cc
@@ -15,6 +15,10 @@
 #include "ui/gl/android/gl_jni_registrar.h"
 #endif
 
+#ifdef V8_USE_EXTERNAL_STARTUP_DATA
+#include "gin/public/isolate_holder.h"
+#endif
+
 class TestBlinkPlatformSupport : NON_EXPORTED_BASE(public blink::Platform) {
  public:
   virtual ~TestBlinkPlatformSupport();
@@ -73,6 +77,10 @@ void BlinkMediaTestSuite::Initialize() {
   // present.
   media::InitializeMediaLibraryForTesting();
 
+#ifdef V8_USE_EXTERNAL_STARTUP_DATA
+    gin::IsolateHolder::LoadV8Snapshot();
+#endif
+
   blink::initialize(blink_platform_support_.get());
 }