aidl: Set explicit defaults to enum-type fields

Fixes: 179853398
Test: mma in hardware/interfaces/graphics
Change-Id: I6f93bca4ba3c8d538765fc9a811b9050c6142cc3
diff --git a/graphics/common/aidl/aidl_api/android.hardware.graphics.common/current/android/hardware/graphics/common/HardwareBufferDescription.aidl b/graphics/common/aidl/aidl_api/android.hardware.graphics.common/current/android/hardware/graphics/common/HardwareBufferDescription.aidl
index 8b12169..232e023 100644
--- a/graphics/common/aidl/aidl_api/android.hardware.graphics.common/current/android/hardware/graphics/common/HardwareBufferDescription.aidl
+++ b/graphics/common/aidl/aidl_api/android.hardware.graphics.common/current/android/hardware/graphics/common/HardwareBufferDescription.aidl
@@ -21,7 +21,7 @@
   int width;
   int height;
   int layers;
-  android.hardware.graphics.common.PixelFormat format;
-  android.hardware.graphics.common.BufferUsage usage;
+  android.hardware.graphics.common.PixelFormat format = android.hardware.graphics.common.PixelFormat.UNSPECIFIED;
+  android.hardware.graphics.common.BufferUsage usage = android.hardware.graphics.common.BufferUsage.CPU_READ_NEVER;
   int stride;
 }
diff --git a/graphics/common/aidl/android/hardware/graphics/common/HardwareBufferDescription.aidl b/graphics/common/aidl/android/hardware/graphics/common/HardwareBufferDescription.aidl
index e1e3492..078c512 100644
--- a/graphics/common/aidl/android/hardware/graphics/common/HardwareBufferDescription.aidl
+++ b/graphics/common/aidl/android/hardware/graphics/common/HardwareBufferDescription.aidl
@@ -29,7 +29,7 @@
     int width;
     int height;
     int layers;
-    PixelFormat format;
-    BufferUsage usage;
+    PixelFormat format = PixelFormat.UNSPECIFIED;
+    BufferUsage usage = BufferUsage.CPU_READ_NEVER;
     int stride;
 }