libgui: make MAX_FRAME_HISTORY a configurable property

Some devices have particularly large pipelines for decoding video. This
can result in large queues of decoded frames waiting to be displayed. If
the frame event history isn't large enough, then frame events can fall
out of the queue before the buffers are actually rendered, which causes
failures when processing consumer frame events.

Test: manually check that MAX_FRAME_HISTORY is configurable at build

Change-Id: I8bfcc6bf095e775c93a39669840d721417a58113
diff --git a/libs/gui/sysprop/LibGuiProperties.sysprop b/libs/gui/sysprop/LibGuiProperties.sysprop
new file mode 100644
index 0000000..0d54711
--- /dev/null
+++ b/libs/gui/sysprop/LibGuiProperties.sysprop
@@ -0,0 +1,25 @@
+# Copyright (C) 2020 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the License);
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an AS IS BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+module: "android.sysprop.LibGuiProperties"
+owner: Platform
+
+# Indicates how many elements should be present in the frame event histories.
+prop {
+    api_name: "frame_event_history_size"
+    type: Integer
+    scope: Public
+    access: Readonly
+    prop_name: "ro.lib_gui.frame_event_history_size"
+}