Delete HWC2to1Adapter unused code.

HWC2to1Adapter supports forwarding Display requests from device
to client. However hwc1 does not support the request.

Change-Id: Id2e77b18823d319721473b3a8c8838aa20b7daec
diff --git a/services/surfaceflinger/DisplayHardware/HWC2On1Adapter.cpp b/services/surfaceflinger/DisplayHardware/HWC2On1Adapter.cpp
index 40c6715..1727bd6 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2On1Adapter.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWC2On1Adapter.cpp
@@ -808,7 +808,10 @@
         return Error::None;
     }
 
-    *outDisplayRequests = mChanges->getDisplayRequests();
+    // Display requests (HWC2::DisplayRequest) are not supported by hwc1:
+    // A hwc1 has always zero requests for the client.
+    *outDisplayRequests = 0;
+
     uint32_t numWritten = 0;
     for (const auto& request : mChanges->getLayerRequests()) {
         if (numWritten == *outNumElements) {
diff --git a/services/surfaceflinger/DisplayHardware/HWC2On1Adapter.h b/services/surfaceflinger/DisplayHardware/HWC2On1Adapter.h
index daa988c..6868bfd 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2On1Adapter.h
+++ b/services/surfaceflinger/DisplayHardware/HWC2On1Adapter.h
@@ -310,14 +310,6 @@
                         return mLayerRequests;
                     }
 
-                    int32_t getDisplayRequests() const {
-                        int32_t requests = 0;
-                        for (auto request : mDisplayRequests) {
-                            requests |= static_cast<int32_t>(request);
-                        }
-                        return requests;
-                    }
-
                     void addTypeChange(hwc2_layer_t layerId,
                             HWC2::Composition type) {
                         mTypeChanges.insert({layerId, type});
@@ -335,7 +327,6 @@
                             mTypeChanges;
                     std::unordered_map<hwc2_layer_t, HWC2::LayerRequest>
                             mLayerRequests;
-                    std::unordered_set<HWC2::DisplayRequest> mDisplayRequests;
             };
 
             std::shared_ptr<const Config>