Revert "Revert "Add ExternalTexture class into RenderEngine inte..."

Revert submission 14199598-revert-14086921-renderengine-external-tex-QJNBWQMQEU

Reason for revert: Prepare for relanding
Reverted Changes:
I01e65a7f4:Revert "Update WaylandRenderSurface to accomodate ...
I7d58118c1:Revert "Update Readback VTS to align with RenderEn...
I1501890f4:Revert "Add ExternalTexture class into RenderEngin...

Added the following fixes:
1. CachedSet renders to intermediate texture variable rather than
mTexture directly, since mTexture is not guaranteed to be nonnull.
2. Add null check when setting new buffer in BLAST.

Bug: 185524947
Bug: 180767535
Test: builds, boots
Test: librenderengine_test
Change-Id: I52ea82e24336b496d996bbe3e445db0affe1abb8
diff --git a/services/surfaceflinger/RefreshRateOverlay.cpp b/services/surfaceflinger/RefreshRateOverlay.cpp
index 7a3e433..a9fd16c 100644
--- a/services/surfaceflinger/RefreshRateOverlay.cpp
+++ b/services/surfaceflinger/RefreshRateOverlay.cpp
@@ -208,7 +208,8 @@
     return true;
 }
 
-const std::vector<sp<GraphicBuffer>>& RefreshRateOverlay::getOrCreateBuffers(uint32_t fps) {
+const std::vector<std::shared_ptr<renderengine::ExternalTexture>>&
+RefreshRateOverlay::getOrCreateBuffers(uint32_t fps) {
     if (mBufferCache.find(fps) == mBufferCache.end()) {
         // Ensure the range is > 0, so we don't divide by 0.
         const auto rangeLength = std::max(1u, mHighFps - mLowFps);
@@ -222,7 +223,17 @@
         color.g = HIGH_FPS_COLOR.g * fpsScale + LOW_FPS_COLOR.g * (1 - fpsScale);
         color.b = HIGH_FPS_COLOR.b * fpsScale + LOW_FPS_COLOR.b * (1 - fpsScale);
         color.a = ALPHA;
-        mBufferCache.emplace(fps, SevenSegmentDrawer::drawNumber(fps, color, mShowSpinner));
+        auto buffers = SevenSegmentDrawer::drawNumber(fps, color, mShowSpinner);
+        std::vector<std::shared_ptr<renderengine::ExternalTexture>> textures;
+        std::transform(buffers.begin(), buffers.end(), std::back_inserter(textures),
+                       [&](const auto& buffer) -> std::shared_ptr<renderengine::ExternalTexture> {
+                           return std::make_shared<
+                                   renderengine::ExternalTexture>(buffer,
+                                                                  mFlinger.getRenderEngine(),
+                                                                  renderengine::ExternalTexture::
+                                                                          Usage::READABLE);
+                       });
+        mBufferCache.emplace(fps, textures);
     }
 
     return mBufferCache[fps];