diff --git a/dom/media/webrtc/MediaEngineTabVideoSource.cpp b/dom/media/webrtc/MediaEngineTabVideoSource.cpp
index ef543dd087b7..1c6936ea897d 100644
--- a/dom/media/webrtc/MediaEngineTabVideoSource.cpp
+++ b/dom/media/webrtc/MediaEngineTabVideoSource.cpp
@@ -7,6 +7,7 @@
 
 #include "mozilla/gfx/2D.h"
 #include "mozilla/RefPtr.h"
+#include "mozilla/UniquePtrExtensions.h"
 #include "nsGlobalWindow.h"
 #include "nsIDOMClientRect.h"
 #include "nsIDocShell.h"
@@ -247,7 +248,7 @@ MediaEngineTabVideoSource::Draw() {
 
   if (mDataSize < static_cast<size_t>(stride * size.height)) {
     mDataSize = stride * size.height;
-    mData = static_cast<unsigned char*>(malloc(mDataSize));
+    mData = MakeUniqueFallible<unsigned char[]>(mDataSize);
   }
   if (!mData) {
     return;
@@ -278,7 +279,7 @@ MediaEngineTabVideoSource::Draw() {
   RefPtr<layers::ImageContainer> container = layers::LayerManager::CreateImageContainer();
   RefPtr<DrawTarget> dt =
     Factory::CreateDrawTargetForData(BackendType::CAIRO,
-                                     mData.rwget(),
+                                     mData.get(),
                                      size,
                                      stride,
                                      SurfaceFormat::B8G8R8X8);
diff --git a/dom/media/webrtc/MediaEngineTabVideoSource.h b/dom/media/webrtc/MediaEngineTabVideoSource.h
index 99e36f18e474..a3afec00a2fc 100644
--- a/dom/media/webrtc/MediaEngineTabVideoSource.h
+++ b/dom/media/webrtc/MediaEngineTabVideoSource.h
@@ -7,6 +7,7 @@
 #include "ImageContainer.h"
 #include "nsITimer.h"
 #include "mozilla/Monitor.h"
+#include "mozilla/UniquePtr.h"
 #include "nsITabSource.h"
 
 namespace mozilla {
@@ -85,7 +86,7 @@ private:
     int32_t mViewportWidth;
     int32_t mViewportHeight;
     int32_t mTimePerFrame;
-    ScopedFreePtr<unsigned char> mData;
+    UniquePtr<unsigned char[]> mData;
     size_t mDataSize;
     nsCOMPtr<nsPIDOMWindowOuter> mWindow;
     RefPtr<layers::SourceSurfaceImage> mImage;