media: Use base component_export.h for media

Since COMPONENT_EXPORT(MEDIA) is too long, still keep MEDIA_EXPORT. But
instead of defining our own, define it to be COMPONENT_EXPORT(MEDIA).

Bug: None
Change-Id: I0b24844d3227f918ef1d567a405a03356f66d289
Reviewed-on: https://chromium-review.googlesource.com/c/1313879
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605190}

media/BUILD.gn

@@ -77,7 +77,7 @@ config("subcomponent_config") {
   if (is_mac) {
     visibility += [ "//media/base/mac" ]
   }
-  defines = [ "MEDIA_IMPLEMENTATION" ]
+  defines = [ "IS_MEDIA_IMPL" ]
   configs = [
     ":media_config",
     "//build/config/compiler:wexit_time_destructors",

media/base/android/media_drm_bridge_client.h

@@ -25,7 +25,7 @@ class MediaDrmBridgeDelegate;
 // media playback could occur.
 MEDIA_EXPORT void SetMediaDrmBridgeClient(MediaDrmBridgeClient* media_client);
 
-#if defined(MEDIA_IMPLEMENTATION)
+#if defined(IS_MEDIA_IMPL)
 // Getter for the client. Returns nullptr if no customized client is needed.
 MediaDrmBridgeClient* GetMediaDrmBridgeClient();
 #endif

media/base/media_client.h

@@ -27,7 +27,7 @@ class MediaClient;
 MEDIA_EXPORT void SetMediaClient(MediaClient* media_client);
 
 // Media's embedder API should only be used by media.
-#if defined(MEDIA_IMPLEMENTATION) || defined(MEDIA_BLINK_IMPLEMENTATION)
+#if defined(IS_MEDIA_IMPL) || defined(MEDIA_BLINK_IMPLEMENTATION)
 // Getter for the client. Returns NULL if no customized client is needed.
 MEDIA_EXPORT MediaClient* GetMediaClient();
 #endif

media/base/media_export.h

@@ -5,28 +5,8 @@
 #ifndef MEDIA_BASE_MEDIA_EXPORT_H_
 #define MEDIA_BASE_MEDIA_EXPORT_H_
 
-// Define MEDIA_EXPORT so that functionality implemented by the Media module
-// can be exported to consumers.
+#include "base/component_export.h"
 
-#if defined(COMPONENT_BUILD)
-#if defined(WIN32)
-
-#if defined(MEDIA_IMPLEMENTATION)
-#define MEDIA_EXPORT __declspec(dllexport)
-#else
-#define MEDIA_EXPORT __declspec(dllimport)
-#endif  // defined(MEDIA_IMPLEMENTATION)
-
-#else  // defined(WIN32)
-#if defined(MEDIA_IMPLEMENTATION)
-#define MEDIA_EXPORT __attribute__((visibility("default")))
-#else
-#define MEDIA_EXPORT
-#endif
-#endif
-
-#else  // defined(COMPONENT_BUILD)
-#define MEDIA_EXPORT
-#endif
+#define MEDIA_EXPORT COMPONENT_EXPORT(MEDIA)
 
 #endif  // MEDIA_BASE_MEDIA_EXPORT_H_