Linux: fix build with system ffmpeg (Chromium side).

media/base/media_posix.cc

 // Copyright (c) 2012 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 <string>
 
 #include "base/file_path.h"
 #include "base/logging.h"
 #include "base/path_service.h"
 #include "base/stringize_macros.h"
 #include "media/ffmpeg/ffmpeg_common.h"
+
+#if !defined(USE_SYSTEM_FFMPEG)
 #include "third_party/ffmpeg/ffmpeg_stubs.h"
 
 using third_party_ffmpeg::kNumStubModules;
 using third_party_ffmpeg::kModuleFfmpegsumo;
 using third_party_ffmpeg::InitializeStubs;
 using third_party_ffmpeg::StubPathMap;
+#endif  // !defined(USE_SYSTEM_FFMPEG)
 
 namespace media {
 
 // Handy to prevent shooting ourselves in the foot with macro wizardry.
 #if !defined(LIBAVCODEC_VERSION_MAJOR) || \
     !defined(LIBAVFORMAT_VERSION_MAJOR) || \
     !defined(LIBAVUTIL_VERSION_MAJOR)
 #error FFmpeg headers not included!
 #endif
 
@@ skipping 15 matching lines @@
 #endif
 
 // Use a global to indicate whether the library has been initialized or not.  We
 // rely on function level static initialization in InitializeMediaLibrary() to
 // guarantee this is only set once in a thread safe manner.
 static bool g_media_library_is_initialized = false;
 
 static bool InitializeMediaLibraryInternal(const FilePath& module_dir) {
   DCHECK(!g_media_library_is_initialized);
 
+#if defined(USE_SYSTEM_FFMPEG)
+  // No initialization is necessary when using system ffmpeg,
+  // we just link directly with system ffmpeg libraries.
+  g_media_library_is_initialized = true;
+#else
   StubPathMap paths;
 
   // First try to initialize with Chrome's sumo library.
   DCHECK_EQ(kNumStubModules, 1);
   paths[kModuleFfmpegsumo].push_back(module_dir.Append(kSumoLib).value());
 
   // If that fails, see if any system libraries are available.
   paths[kModuleFfmpegsumo].push_back(module_dir.Append(
       FILE_PATH_LITERAL(DSO_NAME("avutil", AVUTIL_VERSION))).value());
   paths[kModuleFfmpegsumo].push_back(module_dir.Append(
       FILE_PATH_LITERAL(DSO_NAME("avcodec", AVCODEC_VERSION))).value());
   paths[kModuleFfmpegsumo].push_back(module_dir.Append(
       FILE_PATH_LITERAL(DSO_NAME("avformat", AVFORMAT_VERSION))).value());
 
   g_media_library_is_initialized = InitializeStubs(paths);
+#endif  // !defined(USE_SYSTEM_FFMPEG)
   return g_media_library_is_initialized;
 }
 
 bool InitializeMediaLibrary(const FilePath& base_path) {
   static const bool kMediaLibraryInitialized =
       InitializeMediaLibraryInternal(base_path);
   DCHECK_EQ(kMediaLibraryInitialized, g_media_library_is_initialized);
   return kMediaLibraryInitialized;
 }
 
 void InitializeMediaLibraryForTesting() {
   FilePath file_path;
   CHECK(PathService::Get(base::DIR_EXE, &file_path));
   CHECK(InitializeMediaLibrary(file_path));
 }
 
 bool IsMediaLibraryInitialized() {
   return g_media_library_is_initialized;
 }
 
 }  // namespace media