composer 2.4: add api to control vsync period

Add new functions to improve vsync period switching by the platform:
 - Adding a list of supported vsync periods to Config to avoid the need to expose
   separate Configs for each vsync period.
 - Adding an API to set the vsync period with timeline constraints to allow better
   synchronization with vsync period change.
 - Extending onVsync() callback to provide the current vsync period.

Test: rev up composer to 2.4 and test refresh rate switching
Bug: 141329414
Change-Id: I1a6f395d9634edadc68649d02f624f00173ec519
diff --git a/graphics/composer/2.4/IComposerCallback.hal b/graphics/composer/2.4/IComposerCallback.hal
new file mode 100644
index 0000000..5c3f8bd
--- /dev/null
+++ b/graphics/composer/2.4/IComposerCallback.hal
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2019 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.
+ */
+
+package android.hardware.graphics.composer@2.4;
+
+import @2.1::Display;
+import @2.1::IComposerCallback;
+
+interface IComposerCallback extends @2.1::IComposerCallback {
+    /**
+     * Notifies the client that a vsync event has occurred. This callback must
+     * only be triggered when vsync is enabled for this display (through
+     * setVsyncEnabled).
+     *
+     * @param display is the display which has received a vsync event
+     * @param timestamp is the CLOCK_MONOTONIC time at which the vsync event
+     *        occurred, in nanoseconds.
+     * @param vsyncPeriodNanos is the display vsync period in nanoseconds i.e. the next onVsync_2_4
+     *        is expected to be called vsyncPeriodNanos nanoseconds after this call.
+     */
+    oneway onVsync_2_4(Display display, int64_t timestamp, VsyncPeriodNanos vsyncPeriodNanos);
+};