Bug 1727489 - Remove PLayerTransaction. r=jrmuizel,jgilbert

dom/base/nsDOMWindowUtils.cpp

dom/canvas/ClientWebGLContext.cpp

dom/canvas/HostWebGLContext.cpp

dom/canvas/PWebGL.ipdl

dom/canvas/WebGLParent.cpp

dom/ipc/BrowserChild.cpp

gfx/layers/apz/src/AsyncPanZoomController.cpp

gfx/layers/apz/util/APZCCallbackHelper.cpp

gfx/layers/client/ImageClient.cpp

gfx/layers/ipc/CompositorBridgeChild.cpp

gfx/layers/ipc/CompositorBridgeChild.h

gfx/layers/ipc/CompositorBridgeParent.cpp

gfx/layers/ipc/CompositorBridgeParent.h

gfx/layers/ipc/ContentCompositorBridgeParent.cpp

gfx/layers/ipc/ContentCompositorBridgeParent.h

gfx/layers/ipc/KnowsCompositor.cpp

gfx/layers/ipc/LayerTransactionChild.cpp

gfx/layers/ipc/LayerTransactionChild.h

gfx/layers/ipc/LayerTransactionParent.cpp

gfx/layers/ipc/LayerTransactionParent.h