HWC2: Optimize execution by caching all HWC2 calls in setPerFrameData

To avoid redundant HWC2 calls into hwcomposer service, we cache all HWC2
calls in BufferLayer::setPerFrameData by having visible region, damage
region and layer buffers cached in HWC2::Layer.

Bug: 119414178
Test: Display function test on F2.
Test: b/129317072 Display function tests on M1/S1, M2/S2, B1/C1, B4/S4,
      and C2/F2.
Change-Id: I1679e755ac55a459c93b42b9f8225f0c270228e6
diff --git a/services/surfaceflinger/DisplayHardware/HWC2.h b/services/surfaceflinger/DisplayHardware/HWC2.h
index 4209e45..e0a5ef1 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2.h
+++ b/services/surfaceflinger/DisplayHardware/HWC2.h
@@ -27,6 +27,7 @@
 #include <math/mat4.h>
 #include <ui/GraphicTypes.h>
 #include <ui/HdrCapabilities.h>
+#include <ui/Region.h>
 #include <utils/Log.h>
 #include <utils/StrongPointer.h>
 #include <utils/Timers.h>
@@ -42,8 +43,6 @@
     class Fence;
     class FloatRect;
     class GraphicBuffer;
-    class Rect;
-    class Region;
     namespace Hwc2 {
         class Composer;
     }
@@ -438,9 +437,15 @@
 
     hwc2_display_t mDisplayId;
     hwc2_layer_t mId;
+
+    // Cached HWC2 data, to ensure the same commands aren't sent to the HWC
+    // multiple times.
+    android::Region mVisibleRegion = android::Region::INVALID_REGION;
+    android::Region mDamageRegion = android::Region::INVALID_REGION;
     android::ui::Dataspace mDataSpace = android::ui::Dataspace::UNKNOWN;
     android::HdrMetadata mHdrMetadata;
     android::mat4 mColorMatrix;
+    uint32_t mBufferSlot;
 };
 
 } // namespace impl