hwc2: rename the enable_drop_refresh property to enable_optimize_refresh

Add change to rename the enable_drop_refresh property to
enable_optimize_refresh for better readability.

Change-Id: I379b7ef610bc0979b9a78dac607f371acfe24fbc
CRs-Fixed: 2418804
diff --git a/composer/hwc_display_builtin.cpp b/composer/hwc_display_builtin.cpp
index 635fb22..8b41971 100644
--- a/composer/hwc_display_builtin.cpp
+++ b/composer/hwc_display_builtin.cpp
@@ -120,10 +120,10 @@
   color_mode_ = new HWCColorMode(display_intf_);
   color_mode_->Init();
 
-  int drop_refresh = 0;
-  HWCDebugHandler::Get()->GetProperty(ENABLE_DROP_REFRESH, &drop_refresh);
-  enable_drop_refresh_ = (drop_refresh == 1);
-  if (enable_drop_refresh_) {
+  int optimize_refresh = 0;
+  HWCDebugHandler::Get()->GetProperty(ENABLE_OPTIMIZE_REFRESH, &optimize_refresh);
+  enable_optimize_refresh_ = (optimize_refresh == 1);
+  if (enable_optimize_refresh_) {
     DLOGI("Drop redundant drawcycles %d", id_);
   }
 
@@ -233,7 +233,7 @@
   }
 
   bool vsync_source = (callbacks_->GetVsyncSource() == id_);
-  bool skip_commit = enable_drop_refresh_ && !pending_commit_ && !buffers_latched &&
+  bool skip_commit = enable_optimize_refresh_ && !pending_commit_ && !buffers_latched &&
                      !pending_refresh_ && !vsync_source;
   pending_refresh_ = false;