content: pepper: factorize file descriptor access

BUG=none
TEST=try bots

Review URL: https://codereview.chromium.org/981463004

Cr-Commit-Position: refs/heads/master@{#319449}
diff --git a/content/renderer/pepper/pepper_audio_input_host.cc b/content/renderer/pepper/pepper_audio_input_host.cc
index 0da9cd1..e96e7ea3 100644
--- a/content/renderer/pepper/pepper_audio_input_host.cc
+++ b/content/renderer/pepper/pepper_audio_input_host.cc
@@ -6,6 +6,7 @@
 
 #include "base/logging.h"
 #include "build/build_config.h"
+#include "content/common/pepper_file_util.h"
 #include "content/renderer/pepper/pepper_media_device_manager.h"
 #include "content/renderer/pepper/pepper_platform_audio_input.h"
 #include "content/renderer/pepper/pepper_plugin_instance_impl.h"
@@ -26,17 +27,6 @@
   return socket.handle();
 }
 
-base::PlatformFile ConvertSharedMemoryHandle(
-    const base::SharedMemory& shared_memory) {
-#if defined(OS_POSIX)
-  return shared_memory.handle().fd;
-#elif defined(OS_WIN)
-  return shared_memory.handle();
-#else
-#error "Platform not supported."
-#endif
-}
-
 }  // namespace
 
 PepperAudioInputHost::PepperAudioInputHost(RendererPpapiHostImpl* host,
@@ -183,7 +173,7 @@
     return PP_ERROR_FAILED;
 
   *remote_shared_memory_handle = renderer_ppapi_host_->ShareHandleWithRemote(
-      ConvertSharedMemoryHandle(shared_memory), false);
+      PlatformFileFromSharedMemoryHandle(shared_memory.handle()), false);
   if (*remote_shared_memory_handle == IPC::InvalidPlatformFileForTransit())
     return PP_ERROR_FAILED;