Remove LazyInstance usage from media/

media/base/media.cc

 // Copyright 2013 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 "media/base/media.h"
 
 #include "base/command_line.h"
-#include "base/lazy_instance.h"
 #include "base/macros.h"
 #include "base/metrics/field_trial.h"
 #include "base/trace_event/trace_event.h"
 #include "media/base/media_switches.h"
 #include "media/base/yuv_convert.h"
 
 #if defined(OS_ANDROID)
 #include "base/android/build_info.h"
 #include "media/base/android/media_codec_util.h"
 #endif
 
 #if !defined(MEDIA_DISABLE_FFMPEG)
 #include "media/ffmpeg/ffmpeg_common.h"
 #endif
 
 namespace media {
 
-// Media must only be initialized once, so use a LazyInstance to ensure this.
+// Media must only be initialized once; use a thread-safe static to do this.
 class MediaInitializer {
  public:
-  void enable_platform_decoder_support() {
-    has_platform_decoder_support_ = true;
-  }
-
-  bool has_platform_decoder_support() { return has_platform_decoder_support_; }
-
- private:
-  friend struct base::DefaultLazyInstanceTraits<MediaInitializer>;
-
   MediaInitializer() {
     TRACE_EVENT_WARMUP_CATEGORY("audio");
     TRACE_EVENT_WARMUP_CATEGORY("media");
 
     // Perform initialization of libraries which require runtime CPU detection.
     InitializeCPUSpecificYUVConversions();
 
 #if !defined(MEDIA_DISABLE_FFMPEG)
     // Initialize CPU flags outside of the sandbox as this may query /proc for
     // details on the current CPU for NEON, VFP, etc optimizations.
     av_get_cpu_flags();
 
     // Disable logging as it interferes with layout tests.
     av_log_set_level(AV_LOG_QUIET);
 
 #if defined(ALLOCATOR_SHIM)
     // Remove allocation limit from ffmpeg, so calls go down to shim layer.
     av_max_alloc(0);
 #endif  // defined(ALLOCATOR_SHIM)
 
 #endif  // !defined(MEDIA_DISABLE_FFMPEG)
   }
 
-  ~MediaInitializer() {
-    NOTREACHED() << "MediaInitializer should be leaky!";
+  void enable_platform_decoder_support() {
+    has_platform_decoder_support_ = true;
   }
 
+  bool has_platform_decoder_support() { return has_platform_decoder_support_; }
+
+ private:
+  ~MediaInitializer() { NOTREACHED() << "MediaInitializer should be leaky!"; }

[scottmg, 2017/01/31 21:10:34]

Probably better just to remove this?

[Mark Mentovai, 2017/01/31 21:33:56]

Use

  ~MediaInitializer() = delete;

instead. That’ll make accidental deletion a build-time error, which is better
than a run-time error.

[DaleCurtis, 2017/01/31 22:04:33]

Good idea. Done.

+
   bool has_platform_decoder_support_ = false;

[Mark Mentovai, 2017/01/31 21:33:56]

I don’t think anything is going to be smart enough to optimize this away on
non-Android, even though it looks like this is only used/usable on Android. It’s
not a huge deal in this case, and doesn’t even have any impact on memory
consumption because even if it were gone, MediaInitializer wouldn’t be allowed
to be zero-sized, but I’m mentioning it in case this pattern is in use
elsewhere.

[DaleCurtis, 2017/01/31 22:04:33]

Thanks for the commentary. When I wrote this I just forgot to include
#OS_ANDROID blocks.

 
   DISALLOW_COPY_AND_ASSIGN(MediaInitializer);
 };
 
-static base::LazyInstance<MediaInitializer>::Leaky g_media_library =
-    LAZY_INSTANCE_INITIALIZER;
+static MediaInitializer* GetMediaInstance() {
+  static MediaInitializer* instance = new MediaInitializer();
+  return instance;
+}
 
 void InitializeMediaLibrary() {
-  g_media_library.Get();
+  GetMediaInstance();
 }
 
 #if defined(OS_ANDROID)
 void EnablePlatformDecoderSupport() {
-  g_media_library.Pointer()->enable_platform_decoder_support();
+  GetMediaInstance()->enable_platform_decoder_support();
 }
 
 bool HasPlatformDecoderSupport() {
-  return g_media_library.Pointer()->has_platform_decoder_support();
+  return GetMediaInstance()->has_platform_decoder_support();
 }
 
 bool PlatformHasOpusSupport() {
   return base::android::BuildInfo::GetInstance()->sdk_int() >= 21;
 }
 
 bool IsUnifiedMediaPipelineEnabled() {
   return !base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kDisableUnifiedMediaPipeline);
 }
 
 bool ArePlatformDecodersAvailable() {
   return IsUnifiedMediaPipelineEnabled()
              ? HasPlatformDecoderSupport()
              : MediaCodecUtil::IsMediaCodecAvailable();
 }
 #endif
 
 }  // namespace media