Bug 1176363 - Make a raw copy of each Canvas::CaptureStream frame. r=mattwoodrow

--HG--
extra : rebase_source : 0658dae3991f6839d93aa3a7d4165330307b74a5

dom/media/CanvasCaptureMediaStream.cpp

@@ -8,9 +8,10 @@
 #include "gfxPlatform.h"
 #include "ImageContainer.h"
 #include "MediaStreamGraph.h"
-#include "mozilla/Mutex.h"
 #include "mozilla/dom/CanvasCaptureMediaStreamBinding.h"
 #include "mozilla/dom/HTMLCanvasElement.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/Mutex.h"
 #include "nsContentUtils.h"
 
 using namespace mozilla::layers;
@@ -204,15 +205,42 @@ public:
       return NS_ERROR_FAILURE;
     }
 
-    RefPtr<SourceSurface> opt = gfxPlatform::GetPlatform()
+    RefPtr<DataSourceSurface> data = snapshot->GetDataSurface();
-      ->ScreenReferenceDrawTarget()->OptimizeSourceSurface(snapshot);
+    if (!data) {
-    if (!opt) {
       return NS_ERROR_FAILURE;
     }
 
+    RefPtr<DataSourceSurface> copy;
+
+    {
+      DataSourceSurface::ScopedMap read(data, DataSourceSurface::READ);
+      if (!read.IsMapped()) {
+        return NS_ERROR_FAILURE;
+      }
+
+      copy = Factory::CreateDataSourceSurfaceWithStride(data->GetSize(),
+                                                        data->GetFormat(),
+                                                        read.GetStride());
+      if (!copy) {
+        return NS_ERROR_FAILURE;
+      }
+
+      DataSourceSurface::ScopedMap write(copy, DataSourceSurface::WRITE);
+      if (!write.IsMapped()) {
+        return NS_ERROR_FAILURE;
+      }
+
+      MOZ_ASSERT(read.GetStride() == write.GetStride());
+      MOZ_ASSERT(data->GetSize() == copy->GetSize());
+      MOZ_ASSERT(data->GetFormat() == copy->GetFormat());
+
+      memcpy(write.GetData(), read.GetData(),
+             write.GetStride() * copy->GetSize().height);
+    }
+
     CairoImage::Data imageData;
-    imageData.mSize = opt->GetSize();
+    imageData.mSize = copy->GetSize();
-    imageData.mSourceSurface = opt;
+    imageData.mSourceSurface = copy;
 
     RefPtr<CairoImage> image = new layers::CairoImage();
     image->SetData(imageData);