Revert of Remove unsafe cast from ImageTransportSurfaceOverlayMac::ScheduleCALayer.

gpu/ipc/service/image_transport_surface_overlay_mac.mm

Index: gpu/ipc/service/image_transport_surface_overlay_mac.mm
diff --git a/gpu/ipc/service/image_transport_surface_overlay_mac.mm b/gpu/ipc/service/image_transport_surface_overlay_mac.mm
index 764e45ad44a59b7e5b6c7b6920c92139f51a97eb..f2da74fdc5503df73540cc2cd58b3f29fcbf3a2b 100644
--- a/gpu/ipc/service/image_transport_surface_overlay_mac.mm
+++ b/gpu/ipc/service/image_transport_surface_overlay_mac.mm
@@ -163,9 +163,9 @@
     gpu::TextureInUseResponse response;
     response.texture = query.texture;
     bool in_use = false;
-    gl::GLImageIOSurface* io_surface_image =
-        gl::GLImageIOSurface::FromGLImage(query.image.get());
-    if (io_surface_image) {
+    if (query.image) {
+      gl::GLImageIOSurface* io_surface_image =
+          static_cast<gl::GLImageIOSurface*>(query.image.get());
       in_use = io_surface_image->CanCheckIOSurfaceIsInUse() &&
                IOSurfaceIsInUse(io_surface_image->io_surface());
     }
@@ -320,14 +320,8 @@
     DLOG(ERROR) << "Invalid non-zero Z order.";
     return false;
   }
-  gl::GLImageIOSurface* io_surface_image =
-      gl::GLImageIOSurface::FromGLImage(image);
-  if (!io_surface_image) {
-    DLOG(ERROR) << "Not an IOSurface image.";
-    return false;
-  }
   return ca_layer_tree_coordinator_->SetPendingGLRendererBackbuffer(
-      io_surface_image->io_surface());
+      static_cast<gl::GLImageIOSurface*>(image)->io_surface());
 }
 
 bool ImageTransportSurfaceOverlayMac::ScheduleCALayer(
@@ -342,14 +336,14 @@
     const gfx::Transform& transform,
     int sorting_context_id,
     unsigned filter) {
-  gl::GLImageIOSurface* io_surface_image =
-      gl::GLImageIOSurface::FromGLImage(contents_image);
-  if (!io_surface_image)
-    return false;
-  base::ScopedCFTypeRef<IOSurfaceRef> io_surface =
-      io_surface_image->io_surface();
-  base::ScopedCFTypeRef<CVPixelBufferRef> cv_pixel_buffer =
-      io_surface_image->cv_pixel_buffer();
+  base::ScopedCFTypeRef<IOSurfaceRef> io_surface;
+  base::ScopedCFTypeRef<CVPixelBufferRef> cv_pixel_buffer;
+  if (contents_image) {
+    gl::GLImageIOSurface* io_surface_image =
+        static_cast<gl::GLImageIOSurface*>(contents_image);
+    io_surface = io_surface_image->io_surface();
+    cv_pixel_buffer = io_surface_image->cv_pixel_buffer();
+  }
   return ca_layer_tree_coordinator_->GetPendingCARendererLayerTree()
       ->ScheduleCALayer(is_clipped, gfx::ToEnclosingRect(clip_rect),
                         sorting_context_id, transform, io_surface,