Bug 1406507 - Use an ipc::ByteBuf instead of ByteBuffer to send the DisplayList instead of a ByteBuffer. r=kats

DONTBUILD because this is a backout/reland to make sure the code is associated
with the right bug.

MozReview-Commit-ID: GPQABR9ONld

gfx/layers/ipc/PWebRenderBridge.ipdl

@@ -50,7 +50,7 @@ parent:
   sync Create(IntSize aSize);
   async DeleteCompositorAnimations(uint64_t[] aIds);
   async SetDisplayList(IntSize aSize, WebRenderParentCommand[] commands, OpDestroy[] toDestroy, uint64_t fwdTransactionId, uint64_t transactionId,
-                       LayoutSize aContentSize, ByteBuffer aDL, BuiltDisplayListDescriptor aDLDesc,
+                       LayoutSize aContentSize, ByteBuf aDL, BuiltDisplayListDescriptor aDLDesc,
                        WebRenderScrollData aScrollData,
                        OpUpdateResource[] aResourceUpdates, Shmem[] aSmallShmems, Shmem[] aLargeShmems,
                        IdNamespace aIdNamespace, TimeStamp txnStartTime, TimeStamp fwdTime);

gfx/layers/wr/WebRenderBridgeChild.cpp

@@ -144,7 +144,9 @@ WebRenderBridgeChild::EndTransaction(const wr::LayoutSize& aContentSize,
   MOZ_ASSERT(!mDestroyed);
   MOZ_ASSERT(mIsInTransaction);
 
-  ByteBuffer dlData(Move(aDL.dl));
+  ByteBuf dlData(aDL.dl.inner.data, aDL.dl.inner.length, aDL.dl.inner.capacity);
+  aDL.dl.inner.capacity = 0;
+  aDL.dl.inner.data = nullptr;
 
   TimeStamp fwdTime;
 #if defined(ENABLE_FRAME_LATENCY_LOG)

gfx/layers/wr/WebRenderBridgeParent.cpp

@@ -561,7 +561,7 @@ WebRenderBridgeParent::RecvSetDisplayList(const gfx::IntSize& aSize,
                                           const uint64_t& aFwdTransactionId,
                                           const uint64_t& aTransactionId,
                                           const wr::LayoutSize& aContentSize,
-                                          const wr::ByteBuffer& dl,
+                                          ipc::ByteBuf&& dl,
                                           const wr::BuiltDisplayListDescriptor& dlDesc,
                                           const WebRenderScrollData& aScrollData,
                                           nsTArray<OpUpdateResource>&& aResourceUpdates,
@@ -609,7 +609,7 @@ WebRenderBridgeParent::RecvSetDisplayList(const gfx::IntSize& aSize,
     gfx::Color clearColor(0.f, 0.f, 0.f, 0.f);
     mApi->SetDisplayList(clearColor, wr::NewEpoch(wrEpoch), LayerSize(aSize.width, aSize.height),
                         mPipelineId, aContentSize,
-                        dlDesc, dl.mData, dl.mLength,
+                        dlDesc, dl.mData, dl.mLen,
                         resources);
 
     ScheduleComposition();

gfx/layers/wr/WebRenderBridgeParent.h

@@ -82,7 +82,7 @@ public:
                                              const uint64_t& aFwdTransactionId,
                                              const uint64_t& aTransactionId,
                                              const wr::LayoutSize& aContentSize,
-                                             const wr::ByteBuffer& dl,
+                                             ipc::ByteBuf&& dl,
                                              const wr::BuiltDisplayListDescriptor& dlDesc,
                                              const WebRenderScrollData& aScrollData,
                                              nsTArray<OpUpdateResource>&& aResourceUpdates,