media: Limit kVp9kSVCHWDecoding feature option to ChromeOS x86 devices

This CL limits kVp9kSVCHWDecoding feature option to ChromeOS x86 devices.
ChromeOS ARM devices are not ready for the feature. If I enable the feature on
ARM device by finch experiment, then something wrong happens.

Bug: chromium:935411
Test: Hangout Meet with VP9 SVC stream
Change-Id: I4114d5ab400d4f43bc2d329675c781365e698856
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1768217
Reviewed-by: Dan Sanders <sandersd@chromium.org>
Commit-Queue: Hirokazu Honda <hiroh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#690576}

diff --git a/media/base/media_switches.cc b/media/base/media_switches.cc
index 2e331a0..d6d1f7c 100644
--- a/media/base/media_switches.cc
+++ b/media/base/media_switches.cc

@@ -324,9 +324,11 @@
 const base::Feature kVaapiVP9Encoder{"VaapiVP9Encoder",
                                      base::FEATURE_DISABLED_BY_DEFAULT};
 
+#if defined(ARCH_CPU_X86_FAMILY) && defined(OS_CHROMEOS)
 // Enable VP9 k-SVC decoding with HW decoder for webrtc use case on ChromeOS.
 const base::Feature kVp9kSVCHWDecoding{"Vp9kSVCHWDecoding",
                                        base::FEATURE_DISABLED_BY_DEFAULT};
+#endif  //  defined(ARCH_CPU_X86_FAMILY) && defined(OS_CHROMEOS)
 
 // Inform video blitter of video color space.
 const base::Feature kVideoBlitColorAccuracy{"video-blit-color-accuracy",

diff --git a/media/base/media_switches.h b/media/base/media_switches.h
index 35eaeef..8dc7d05 100644
--- a/media/base/media_switches.h
+++ b/media/base/media_switches.h

@@ -139,11 +139,14 @@
 MEDIA_EXPORT extern const base::Feature kVaapiLowPowerEncoder;
 MEDIA_EXPORT extern const base::Feature kVaapiVP8Encoder;
 MEDIA_EXPORT extern const base::Feature kVaapiVP9Encoder;
-MEDIA_EXPORT extern const base::Feature kVp9kSVCHWDecoding;
 MEDIA_EXPORT extern const base::Feature kVideoBlitColorAccuracy;
 MEDIA_EXPORT extern const base::Feature kWidevineAv1;
 MEDIA_EXPORT extern const base::Feature kWidevineAv1ForceSupportForTesting;
 
+#if defined(ARCH_CPU_X86_FAMILY) && defined(OS_CHROMEOS)
+MEDIA_EXPORT extern const base::Feature kVp9kSVCHWDecoding;
+#endif  // defined(ARCH_CPU_X86_FAMILY) && defined(OS_CHROMEOS)
+
 #if defined(OS_ANDROID)
 MEDIA_EXPORT extern const base::Feature kMediaControlsExpandGesture;
 MEDIA_EXPORT extern const base::Feature kMediaDrmPersistentLicense;

diff --git a/media/gpu/vp9_decoder.cc b/media/gpu/vp9_decoder.cc
index 68188ea4..59668bd 100644
--- a/media/gpu/vp9_decoder.cc
+++ b/media/gpu/vp9_decoder.cc

@@ -9,6 +9,7 @@
 #include "base/bind.h"
 #include "base/feature_list.h"
 #include "base/logging.h"
+#include "build/build_config.h"
 #include "media/base/limits.h"
 #include "media/base/media_switches.h"
 #include "media/gpu/vp9_decoder.h"
@@ -18,6 +19,7 @@
 namespace {
 std::vector<uint32_t> GetSpatialLayerFrameSize(
     const DecoderBuffer& decoder_buffer) {
+#if defined(ARCH_CPU_X86_FAMILY) && defined(OS_CHROMEOS)
   const uint32_t* cue_data =
       reinterpret_cast<const uint32_t*>(decoder_buffer.side_data());
   if (!cue_data)
@@ -33,6 +35,8 @@
     return {};
   }
   return std::vector<uint32_t>(cue_data, cue_data + num_of_layers);
+#endif  // defined(ARCH_CPU_X86_FAMILY) && defined(OS_CHROMEOS)
+  return {};
 }
 }  // namespace