Move utility classes in a separate static target

Split up utility classes that can be re-used in other IComposer related
tests (such as the IVrComposerClient tests).

Changes:
 * Move GraphicsComposerCallback into separate module
 * Extract TestCommandReader in separate module
 * Extract Composer::execute() from test class

Bug: 38203529
Test: Compiled
Change-Id: I0d1193469e9dd94c477a63058f98111c162dfa99
diff --git a/graphics/composer/2.1/vts/functional/TestCommandReader.cpp b/graphics/composer/2.1/vts/functional/TestCommandReader.cpp
new file mode 100644
index 0000000..b1f9aca
--- /dev/null
+++ b/graphics/composer/2.1/vts/functional/TestCommandReader.cpp
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 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.
+ */
+
+#include "TestCommandReader.h"
+
+#include <gtest/gtest.h>
+
+namespace android {
+namespace hardware {
+namespace graphics {
+namespace composer {
+namespace V2_1 {
+namespace tests {
+
+void TestCommandReader::parse() {
+  while (!isEmpty()) {
+    IComposerClient::Command command;
+    uint16_t length;
+    ASSERT_TRUE(beginCommand(&command, &length));
+
+    switch (command) {
+      case IComposerClient::Command::SET_ERROR: {
+        ASSERT_EQ(2, length);
+        auto loc = read();
+        auto err = readSigned();
+        GTEST_FAIL() << "unexpected error " << err << " at location " << loc;
+      } break;
+      case IComposerClient::Command::SELECT_DISPLAY:
+      case IComposerClient::Command::SET_CHANGED_COMPOSITION_TYPES:
+      case IComposerClient::Command::SET_DISPLAY_REQUESTS:
+      case IComposerClient::Command::SET_PRESENT_FENCE:
+      case IComposerClient::Command::SET_RELEASE_FENCES:
+        break;
+      default:
+        GTEST_FAIL() << "unexpected return command " << std::hex
+                     << static_cast<int>(command);
+        break;
+    }
+
+    endCommand();
+  }
+}
+
+}  // namespace tests
+}  // namespace V2_1
+}  // namespace composer
+}  // namespace graphics
+}  // namespace hardware
+}  // namespace android