Fix the FFmpeg extension build

Since gradle 4.0, CMake imported libraries are bundled in the APK, so
manually bundling them causes a duplication which breaks the build.

Issue: #7906
PiperOrigin-RevId: 332012375

extensions/ffmpeg/build.gradle

@@ -13,13 +13,6 @@
 // limitations under the License.
 apply from: "$gradle.ext.exoplayerSettingsDir/common_library_config.gradle"
 
-android {
-    sourceSets.main {
-        // The directory from which to pick the ffmpeg binaries.
-        jniLibs.srcDir 'src/main/libs'
-    }
-}
-
 // Configure the native build only if ffmpeg is present to avoid gradle sync
 // failures if ffmpeg hasn't been built according to the README instructions.
 if (project.file('src/main/jni/ffmpeg').exists()) {

extensions/ffmpeg/src/main/jni/CMakeLists.txt

@@ -7,7 +7,6 @@ project(libffmpeg_jni C CXX)
 
 set(ffmpeg_location "${CMAKE_CURRENT_SOURCE_DIR}/ffmpeg")
 set(ffmpeg_binaries "${ffmpeg_location}/android-libs/${ANDROID_ABI}")
-set(ffmpeg_output_dir "${CMAKE_CURRENT_SOURCE_DIR}/../libs/${ANDROID_ABI}")
 
 foreach(ffmpeg_lib avutil swresample avcodec)
     set(ffmpeg_lib_filename lib${ffmpeg_lib}.so)
@@ -20,7 +19,6 @@ foreach(ffmpeg_lib avutil swresample avcodec)
             ${ffmpeg_lib} PROPERTIES
             IMPORTED_LOCATION
             ${ffmpeg_lib_file_path})
-    file(COPY ${ffmpeg_lib_file_path} DESTINATION ${ffmpeg_output_dir})
 endforeach()
 
 include_directories(${ffmpeg_location})