SF: Clean up DisplayDeviceState

The DisplayDevice::DisplayType in DisplayDeviceState will be replaced
with a DisplayId in a follow-up CL, so this CL removes unnecessary
constructors and renames displayId to sequenceId.

Bug: 74619554
Test: Build
Change-Id: I994042188299d59a62a368c12455d04891d07298
diff --git a/services/surfaceflinger/DisplayDevice.h b/services/surfaceflinger/DisplayDevice.h
index d7c5b26..dd69404 100644
--- a/services/surfaceflinger/DisplayDevice.h
+++ b/services/surfaceflinger/DisplayDevice.h
@@ -267,15 +267,10 @@
 };
 
 struct DisplayDeviceState {
-    DisplayDeviceState() = default;
-    DisplayDeviceState(DisplayDevice::DisplayType type, bool isSecure);
-
     bool isValid() const { return type >= 0; }
-    bool isMainDisplay() const { return type == DisplayDevice::DISPLAY_PRIMARY; }
-    bool isVirtualDisplay() const { return type >= DisplayDevice::DISPLAY_VIRTUAL; }
+    bool isVirtual() const { return type >= DisplayDevice::DISPLAY_VIRTUAL; }
 
-    static std::atomic<int32_t> nextDisplayId;
-    int32_t displayId = nextDisplayId++;
+    int32_t sequenceId = sNextSequenceId++;
     DisplayDevice::DisplayType type = DisplayDevice::DISPLAY_ID_INVALID;
     sp<IGraphicBufferProducer> surface;
     uint32_t layerStack = DisplayDevice::NO_LAYER_STACK;
@@ -286,6 +281,9 @@
     uint32_t height = 0;
     std::string displayName;
     bool isSecure = false;
+
+private:
+    static std::atomic<int32_t> sNextSequenceId;
 };
 
 class DisplayRenderArea : public RenderArea {