Bug 1272203 (part 3) - Use NotNull in nsContentUtils::GetSurfaceData(). r=froydnj.

This might not look compelling in isolation, but this use of NotNull would have
prevented the null dereference crash in bug 1268721.

dom/base/nsContentUtils.cpp

@@ -7424,7 +7424,8 @@ nsContentUtils::TransferableToIPCTransferable(nsITransferable* aTransferable,
             size_t length;
             int32_t stride;
             mozilla::UniquePtr<char[]> surfaceData =
-              nsContentUtils::GetSurfaceData(dataSurface, &length, &stride);
+              nsContentUtils::GetSurfaceData(WrapNotNull(dataSurface), &length,
+                                             &stride);
 
             IPCDataTransferItem* item = aIPCDataTransfer->items().AppendElement();
             item->flavor() = flavorStr;
@@ -7528,8 +7529,9 @@ nsContentUtils::TransferableToIPCTransferable(nsITransferable* aTransferable,
 }
 
 mozilla::UniquePtr<char[]>
-nsContentUtils::GetSurfaceData(mozilla::gfx::DataSourceSurface* aSurface,
+nsContentUtils::GetSurfaceData(
-                               size_t* aLength, int32_t* aStride)
+  NotNull<mozilla::gfx::DataSourceSurface*> aSurface,
+  size_t* aLength, int32_t* aStride)
 {
   mozilla::gfx::DataSourceSurface::MappedSurface map;
   if (NS_WARN_IF(!aSurface->Map(mozilla::gfx::DataSourceSurface::MapType::READ, &map))) {

dom/base/nsContentUtils.h

@@ -32,6 +32,7 @@
 #include "mozilla/FloatingPoint.h"
 #include "mozilla/net/ReferrerPolicy.h"
 #include "mozilla/Logging.h"
+#include "mozilla/NotNull.h"
 #include "nsIContentPolicy.h"
 
 #if defined(XP_WIN)
@@ -2432,8 +2433,9 @@ public:
    * Get the pixel data from the given source surface and return it as a buffer.
    * The length and stride will be assigned from the surface.
    */
-  static mozilla::UniquePtr<char[]> GetSurfaceData(mozilla::gfx::DataSourceSurface* aSurface,
+  static mozilla::UniquePtr<char[]> GetSurfaceData(
-                                                   size_t* aLength, int32_t* aStride);
+    mozilla::NotNull<mozilla::gfx::DataSourceSurface*> aSurface,
+    size_t* aLength, int32_t* aStride);
 
   // Helpers shared by the implementations of nsContentUtils methods and
   // nsIDOMWindowUtils methods.

widget/PuppetWidget.cpp

@@ -990,7 +990,7 @@ PuppetWidget::SetCursor(imgIContainer* aCursor,
   size_t length;
   int32_t stride;
   mozilla::UniquePtr<char[]> surfaceData =
-    nsContentUtils::GetSurfaceData(dataSurface, &length, &stride);
+    nsContentUtils::GetSurfaceData(WrapNotNull(dataSurface), &length, &stride);
 
   nsDependentCString cursorData(surfaceData.get(), length);
   mozilla::gfx::IntSize size = dataSurface->GetSize();

widget/nsDragServiceProxy.cpp

@@ -55,7 +55,8 @@ nsDragServiceProxy::InvokeDragSessionImpl(nsISupportsArray* aArrayTransferables,
         size_t length;
         int32_t stride;
         mozilla::UniquePtr<char[]> surfaceData =
-          nsContentUtils::GetSurfaceData(dataSurface, &length, &stride);
+          nsContentUtils::GetSurfaceData(WrapNotNull(dataSurface), &length,
+                                         &stride);
         nsDependentCString dragImage(surfaceData.get(), length);
 
         mozilla::Unused <<