Bug 795648 - Don't synchronously decode images during painting. r=joe

image/src/RasterImage.cpp

@@ -1078,10 +1078,19 @@ RasterImage::GetFrame(uint32_t aWhichFrame,
 already_AddRefed<layers::Image>
 RasterImage::GetCurrentImage()
 {
+  if (!mDecoded) {
+    RequestDecode();
+    return nullptr;
+  }
+
   nsRefPtr<gfxASurface> imageSurface;
-  nsresult rv = GetFrame(FRAME_CURRENT, FLAG_SYNC_DECODE, getter_AddRefs(imageSurface));
+  nsresult rv = GetFrame(FRAME_CURRENT, FLAG_NONE, getter_AddRefs(imageSurface));
   NS_ENSURE_SUCCESS(rv, nullptr);
 
+  if (!imageSurface) {
+    return nullptr;
+  }
+
   if (!mImageContainer) {
     mImageContainer = LayerManager::CreateImageContainer();
   }
@@ -1110,10 +1119,10 @@ RasterImage::GetImageContainer(ImageContainer **_retval)
     NS_ADDREF(*_retval);
     return NS_OK;
   }
-  
+
   nsRefPtr<layers::Image> image = GetCurrentImage();
   if (!image) {
-    return NS_ERROR_FAILURE;
+    return NS_ERROR_NOT_AVAILABLE;
   }
   mImageContainer->SetCurrentImageInTransaction(image);