Bug 1544181 - Check for large frames in GMPDecodeData; r=ng

Differential Revision: https://phabricator.services.mozilla.com/D64341

--HG--
extra : moz-landing-system : lando

media/webrtc/signaling/src/media-conduit/WebrtcGmpVideoCodec.h

@@ -126,6 +126,8 @@ class GMPDecodeData {
         mRenderTimeMs(aRenderTimeMs) {
     // We want to use this for queuing, and the calling code recycles the
     // buffer on return from Decode()
+    MOZ_RELEASE_ASSERT(aInputImage._length <
+                       (std::numeric_limits<size_t>::max() >> 1));
     mImage._length = aInputImage._length;
     mImage._size =
         aInputImage._length +