Mark GenericFrameInfo as an exported symbol

Currently, webrtc can only simulate the GenericDescriptorInfo
based on codec specific info when uses HW encode acceleration.
To provide more accurate description, RTCVideoEncoder in the
chromium blink module needs to fill the generic frame info and
GenericFrameInfo should be marked as exported to chromium.

Bug: chromium:40275246
Change-Id: I34c2747ab32cfdb1be13ae3b1635242f18462de7
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/323063
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Sergey Silkin <ssilkin@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#42738}
diff --git a/common_video/generic_frame_descriptor/BUILD.gn b/common_video/generic_frame_descriptor/BUILD.gn
index fb25d5f..79314f8 100644
--- a/common_video/generic_frame_descriptor/BUILD.gn
+++ b/common_video/generic_frame_descriptor/BUILD.gn
@@ -19,6 +19,7 @@
     "../../api/transport/rtp:dependency_descriptor",
     "../../api/video:video_codec_constants",
     "../../rtc_base:checks",
+    "../../rtc_base/system:rtc_export",
     "//third_party/abseil-cpp/absl/container:inlined_vector",
     "//third_party/abseil-cpp/absl/strings:string_view",
   ]
diff --git a/common_video/generic_frame_descriptor/generic_frame_info.h b/common_video/generic_frame_descriptor/generic_frame_info.h
index 19f413b..30db423 100644
--- a/common_video/generic_frame_descriptor/generic_frame_info.h
+++ b/common_video/generic_frame_descriptor/generic_frame_info.h
@@ -19,6 +19,7 @@
 #include "absl/strings/string_view.h"
 #include "api/transport/rtp/dependency_descriptor.h"
 #include "api/video/video_codec_constants.h"
+#include "rtc_base/system/rtc_export.h"
 
 namespace webrtc {
 
@@ -32,7 +33,7 @@
   bool updated = false;
 };
 
-struct GenericFrameInfo : public FrameDependencyTemplate {
+struct RTC_EXPORT GenericFrameInfo : public FrameDependencyTemplate {
   class Builder;
 
   GenericFrameInfo();