SF: Replace futureOf with ftl::yield in tests

ftl::yield is equivalent and slightly more efficient as of
I9a7ca7de17e7af10515de97d2f6a0dfa24e35d7a.

Bug: 185536303
Test: CompositionTest
Change-Id: I74c8cffa5c228a07302c8d3665044113c0432a02
diff --git a/services/surfaceflinger/tests/unittests/CompositionTest.cpp b/services/surfaceflinger/tests/unittests/CompositionTest.cpp
index beb2147..7d8a30a 100644
--- a/services/surfaceflinger/tests/unittests/CompositionTest.cpp
+++ b/services/surfaceflinger/tests/unittests/CompositionTest.cpp
@@ -25,6 +25,7 @@
 
 #include <compositionengine/Display.h>
 #include <compositionengine/mock/DisplaySurface.h>
+#include <ftl/future.h>
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 #include <gui/IProducerListener.h>
@@ -227,14 +228,6 @@
     LayerCase::cleanup(this);
 }
 
-template <class T>
-std::future<T> futureOf(T obj) {
-    std::promise<T> resultPromise;
-    std::future<T> resultFuture = resultPromise.get_future();
-    resultPromise.set_value(std::move(obj));
-    return resultFuture;
-}
-
 /* ------------------------------------------------------------------------
  * Variants for each display configuration which can be tested
  */
@@ -327,13 +320,13 @@
                 .WillRepeatedly([&](const renderengine::DisplaySettings& displaySettings,
                                     const std::vector<renderengine::LayerSettings>&,
                                     const std::shared_ptr<renderengine::ExternalTexture>&,
-                                    base::unique_fd&&) -> std::future<FenceResult> {
+                                    base::unique_fd&&) -> ftl::Future<FenceResult> {
                     EXPECT_EQ(DEFAULT_DISPLAY_MAX_LUMINANCE, displaySettings.maxLuminance);
                     EXPECT_EQ(Rect(DEFAULT_DISPLAY_WIDTH, DEFAULT_DISPLAY_HEIGHT),
                               displaySettings.physicalDisplay);
                     EXPECT_EQ(Rect(DEFAULT_DISPLAY_WIDTH, DEFAULT_DISPLAY_HEIGHT),
                               displaySettings.clip);
-                    return futureOf<FenceResult>(Fence::NO_FENCE);
+                    return ftl::yield<FenceResult>(Fence::NO_FENCE);
                 });
     }
 
@@ -378,14 +371,14 @@
                 .WillRepeatedly([&](const renderengine::DisplaySettings& displaySettings,
                                     const std::vector<renderengine::LayerSettings>&,
                                     const std::shared_ptr<renderengine::ExternalTexture>&,
-                                    base::unique_fd&&) -> std::future<FenceResult> {
+                                    base::unique_fd&&) -> ftl::Future<FenceResult> {
                     EXPECT_EQ(DEFAULT_DISPLAY_MAX_LUMINANCE, displaySettings.maxLuminance);
                     EXPECT_EQ(Rect(DEFAULT_DISPLAY_WIDTH, DEFAULT_DISPLAY_HEIGHT),
                               displaySettings.physicalDisplay);
                     EXPECT_EQ(Rect(DEFAULT_DISPLAY_WIDTH, DEFAULT_DISPLAY_HEIGHT),
                               displaySettings.clip);
                     EXPECT_EQ(ui::Dataspace::UNKNOWN, displaySettings.outputDataspace);
-                    return futureOf<FenceResult>(Fence::NO_FENCE);
+                    return ftl::yield<FenceResult>(Fence::NO_FENCE);
                 });
     }
 
@@ -578,7 +571,7 @@
                 .WillOnce([&](const renderengine::DisplaySettings& displaySettings,
                               const std::vector<renderengine::LayerSettings>& layerSettings,
                               const std::shared_ptr<renderengine::ExternalTexture>&,
-                              base::unique_fd&&) -> std::future<FenceResult> {
+                              base::unique_fd&&) -> ftl::Future<FenceResult> {
                     EXPECT_EQ(DEFAULT_DISPLAY_MAX_LUMINANCE, displaySettings.maxLuminance);
                     EXPECT_EQ(Rect(DEFAULT_DISPLAY_WIDTH, DEFAULT_DISPLAY_HEIGHT),
                               displaySettings.physicalDisplay);
@@ -586,7 +579,8 @@
                               displaySettings.clip);
                     // screen capture adds an additional color layer as an alpha
                     // prefill, so gtet the back layer.
-                    std::future<FenceResult> resultFuture = futureOf<FenceResult>(Fence::NO_FENCE);
+                    ftl::Future<FenceResult> resultFuture =
+                            ftl::yield<FenceResult>(Fence::NO_FENCE);
                     if (layerSettings.empty()) {
                         ADD_FAILURE() << "layerSettings was not expected to be empty in "
                                          "setupREBufferCompositionCommonCallExpectations "
@@ -627,7 +621,7 @@
                 .WillOnce([&](const renderengine::DisplaySettings& displaySettings,
                               const std::vector<renderengine::LayerSettings>& layerSettings,
                               const std::shared_ptr<renderengine::ExternalTexture>&,
-                              base::unique_fd&&) -> std::future<FenceResult> {
+                              base::unique_fd&&) -> ftl::Future<FenceResult> {
                     EXPECT_EQ(DEFAULT_DISPLAY_MAX_LUMINANCE, displaySettings.maxLuminance);
                     EXPECT_EQ(Rect(DEFAULT_DISPLAY_WIDTH, DEFAULT_DISPLAY_HEIGHT),
                               displaySettings.physicalDisplay);
@@ -635,7 +629,8 @@
                               displaySettings.clip);
                     // screen capture adds an additional color layer as an alpha
                     // prefill, so get the back layer.
-                    std::future<FenceResult> resultFuture = futureOf<FenceResult>(Fence::NO_FENCE);
+                    ftl::Future<FenceResult> resultFuture =
+                            ftl::yield<FenceResult>(Fence::NO_FENCE);
                     if (layerSettings.empty()) {
                         ADD_FAILURE()
                                 << "layerSettings was not expected to be empty in "
@@ -709,7 +704,7 @@
                 .WillOnce([&](const renderengine::DisplaySettings& displaySettings,
                               const std::vector<renderengine::LayerSettings>& layerSettings,
                               const std::shared_ptr<renderengine::ExternalTexture>&,
-                              base::unique_fd&&) -> std::future<FenceResult> {
+                              base::unique_fd&&) -> ftl::Future<FenceResult> {
                     EXPECT_EQ(DEFAULT_DISPLAY_MAX_LUMINANCE, displaySettings.maxLuminance);
                     EXPECT_EQ(Rect(DEFAULT_DISPLAY_WIDTH, DEFAULT_DISPLAY_HEIGHT),
                               displaySettings.physicalDisplay);
@@ -717,7 +712,8 @@
                               displaySettings.clip);
                     // screen capture adds an additional color layer as an alpha
                     // prefill, so get the back layer.
-                    std::future<FenceResult> resultFuture = futureOf<FenceResult>(Fence::NO_FENCE);
+                    ftl::Future<FenceResult> resultFuture =
+                            ftl::yield<FenceResult>(Fence::NO_FENCE);
                     if (layerSettings.empty()) {
                         ADD_FAILURE() << "layerSettings was not expected to be empty in "
                                          "setupInsecureREBufferCompositionCommonCallExpectations "