[SurfaceFlinger] add getDisplayedContentSamplingAttributes i/f

Add interface to ISurfaceComposer that can query the
graphics.composer for querying the displayed content sampling
engine's supported attributes.

Bug: 116028618
Test: Boot
Test: ran test client against prototype, see attributes reported
Test: Ran new test './libgui_test  --gtest_filter="DisplayedContentSamp*"'
Test: on hwc with and without new function hook.
Change-Id: Ie4bebd98d134e63a9f3e21f79ae519a1fe8055b0
diff --git a/libs/gui/tests/DisplayedContentSampling_test.cpp b/libs/gui/tests/DisplayedContentSampling_test.cpp
new file mode 100644
index 0000000..f2c0e0c
--- /dev/null
+++ b/libs/gui/tests/DisplayedContentSampling_test.cpp
@@ -0,0 +1,68 @@
+/*
+ * Copyright 2018 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 <gtest/gtest.h>
+
+#include <binder/ProcessState.h>
+#include <gui/ISurfaceComposer.h>
+#include <gui/Surface.h>
+#include <gui/SurfaceComposerClient.h>
+#include <inttypes.h>
+
+namespace android {
+
+using Transaction = SurfaceComposerClient::Transaction;
+
+static constexpr uint32_t INVALID_MASK = 0x10;
+class DisplayedContentSamplingTest : public ::testing::Test {
+protected:
+    void SetUp() {
+        mComposerClient = new SurfaceComposerClient;
+        ASSERT_EQ(OK, mComposerClient->initCheck());
+        mDisplayToken = mComposerClient->getBuiltInDisplay(ISurfaceComposer::eDisplayIdMain);
+        ASSERT_TRUE(mDisplayToken);
+    }
+
+    bool shouldSkipTest(status_t status) {
+        if (status == PERMISSION_DENIED) {
+            SUCCEED() << "permissions denial, skipping test";
+            return true;
+        }
+        if (status == INVALID_OPERATION) {
+            SUCCEED() << "optional function not supported, skipping test";
+            return true;
+        }
+        return false;
+    }
+
+    sp<SurfaceComposerClient> mComposerClient;
+    sp<IBinder> mDisplayToken;
+};
+
+TEST_F(DisplayedContentSamplingTest, GetDisplayedContentSamplingAttributesAreSane) {
+    ui::PixelFormat format;
+    ui::Dataspace dataspace;
+    uint8_t componentMask = 0;
+    status_t status =
+            mComposerClient->getDisplayedContentSamplingAttributes(mDisplayToken, &format,
+                                                                   &dataspace, &componentMask);
+    if (shouldSkipTest(status)) {
+        return;
+    }
+    EXPECT_EQ(OK, status);
+    EXPECT_LE(componentMask, INVALID_MASK);
+}
+} // namespace android