Add missing null check to AVDA deferred rendering shutdown path.

content/common/gpu/media/android_deferred_rendering_backing_strategy.cc

Index: content/common/gpu/media/android_deferred_rendering_backing_strategy.cc
diff --git a/content/common/gpu/media/android_deferred_rendering_backing_strategy.cc b/content/common/gpu/media/android_deferred_rendering_backing_strategy.cc
index 0bec437888ff5b68ab2ec5459930bd9f975eacc3..660785eea904bd446524425b8be3917280b0562f 100644
--- a/content/common/gpu/media/android_deferred_rendering_backing_strategy.cc
+++ b/content/common/gpu/media/android_deferred_rendering_backing_strategy.cc
@@ -41,6 +41,10 @@ void AndroidDeferredRenderingBackingStrategy::Initialize(
 void AndroidDeferredRenderingBackingStrategy::Cleanup(
     bool have_context,
     const AndroidVideoDecodeAccelerator::OutputBufferMap& buffers) {
+  // If we failed before Initialize, then do nothing.
+  if (!shared_state_)
+    return;
+
   // Make sure that no PictureBuffer textures refer to the SurfaceTexture or to
   // the service_id that we created for it.
   for (const std::pair<int, media::PictureBuffer>& entry : buffers)