[RenderEngine] Only compile Graphite if either Graphite flag is enabled

RE-Graphite will be *compiled* if either the graphite_renderengine
or force_compile_graphite_renderengine ready-only flag is enabled at
compile time (inclusive OR).

RE-Graphite can be compiled and *enabled* by:
1. setting just graphite_renderengine=true, or
2. setting both force_compile_graphite_renderengine=true and the
debug.renderengine.graphite system property to true.

Why RenderEngine needs a dep on libsurfaceflingerflags now:
libsurfaceflinger_common pulls in SF's FlagManager, which is layered on
top of the API that's autogenerated for SF's aconfig module,
libsurfaceflingerflags.
The COM_ANDROID_GRAPHICS_SURFACEFLINGER_FLAGS(...) macro is defined by
com_android_graphics_surfaceflinger_flags.h in that latter aconfig
module, and that header is not exported by the higher-level FlagManager
code.

Bug: b/293371537
Bug: b/331678326
Bug: b/341728634
Test: boot and bloaty (see b/331678326)
Flag: com.android.graphics.surfaceflinger.flags.graphite_renderengine
Change-Id: I9d0b15bda08430552716a9a1f7cd59d91ee7b9a6

1 files changed, 17 insertions, 0 deletions

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 5f81cd45cc..be0c1548d7 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -40,6 +40,7 @@
 #include <binder/IPCThreadState.h>
 #include <binder/IServiceManager.h>
 #include <binder/PermissionCache.h>
+#include <com_android_graphics_surfaceflinger_flags.h>
 #include <common/FlagManager.h>
 #include <compositionengine/CompositionEngine.h>
 #include <compositionengine/CompositionRefreshArgs.h>
@@ -813,8 +814,24 @@ void chooseRenderEngineType(renderengine::RenderEngineCreationArgs::Builder& bui
                 .setGraphicsApi(renderengine::RenderEngine::GraphicsApi::VK);
     } else {
         const auto kVulkan = renderengine::RenderEngine::GraphicsApi::VK;
+// TODO: b/341728634 - Clean up conditional compilation.
+// Note: this guard in particular must check e.g.
+// COM_ANDROID_GRAPHICS_SURFACEFLINGER_FLAGS_GRAPHITE_RENDERENGINE directly (instead of calling e.g.
+// COM_ANDROID_GRAPHICS_SURFACEFLINGER_FLAGS(GRAPHITE_RENDERENGINE)) because that macro is undefined
+// in the libsurfaceflingerflags_test variant of com_android_graphics_surfaceflinger_flags.h, which
+// is used by layertracegenerator (which also needs SurfaceFlinger.cpp). :)
+#if COM_ANDROID_GRAPHICS_SURFACEFLINGER_FLAGS_GRAPHITE_RENDERENGINE || \
+        COM_ANDROID_GRAPHICS_SURFACEFLINGER_FLAGS_FORCE_COMPILE_GRAPHITE_RENDERENGINE
         const bool useGraphite = FlagManager::getInstance().graphite_renderengine() &&
                 renderengine::RenderEngine::canSupport(kVulkan);
+#else
+        const bool useGraphite = false;
+        if (FlagManager::getInstance().graphite_renderengine()) {
+            ALOGE("RenderEngine's Graphite Skia backend was requested with the "
+                  "debug.renderengine.graphite system property, but it is not compiled in this "
+                  "build! Falling back to Ganesh backend selection logic.");
+        }
+#endif
         const bool useVulkan = useGraphite ||
                 (FlagManager::getInstance().vulkan_renderengine() &&
                  renderengine::RenderEngine::canSupport(kVulkan));