Add gralloc usage conversion functions

Converting gralloc1 / ..graphics.allocator@2.0 usage to gralloc0 usage
requires more than just ORing bits and truncating: the CPU_READ_OFTEN
bits don't match up correctly. Add utility functions for converting
back and forth which handle this properly.

Test: boot bullhead-eng
Change-Id: I1cee972feaea486d5607c60acead2e870c2c9549
diff --git a/libgrallocusage/Android.bp b/libgrallocusage/Android.bp
new file mode 100644
index 0000000..54bfee5
--- /dev/null
+++ b/libgrallocusage/Android.bp
@@ -0,0 +1,29 @@
+// Copyright 2017 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.
+
+cc_library_static {
+    name: "libgrallocusage",
+    cppflags: [
+        "-Weverything",
+        "-Werror",
+        "-Wno-c++98-compat-pedantic",
+        // Hide errors in headers we include
+        "-Wno-global-constructors",
+        "-Wno-exit-time-destructors",
+        "-Wno-padded",
+    ],
+    srcs: ["GrallocUsageConversion.cpp"],
+    export_include_dirs: ["include"],
+    shared_libs: ["android.hardware.graphics.allocator@2.0"],
+}