Add r/w opt-in rollout flag for RenderEngine on Graphite

This flag will allow some devices to opt in to RE-Graphite as a preview
rollout progresses. Making it a R/W flag will allow for A/B comparison.

Test: manual validation of aconfig flag / sysprop combos
Bug: b/293371537
Flag: com.android.graphics.surfaceflinger.flags.graphite_renderengine_preview_rollout
Change-Id: I30a59986d1da2dc8355c2b3cf2da436c6cc64120

Author: nscobie

libs/renderengine/include/renderengine/RenderEngine.h

@@ -37,6 +37,14 @@
  */
 #define PROPERTY_DEBUG_RENDERENGINE_BACKEND "debug.renderengine.backend"
 
+/**
+ * Allows opting particular devices into an initial preview rollout of RenderEngine on Graphite.
+ *
+ * Only applicable within SurfaceFlinger, and if relevant aconfig flags are enabled.
+ */
+#define PROPERTY_DEBUG_RENDERENGINE_GRAPHITE_PREVIEW_OPTIN \
+    "debug.renderengine.graphite_preview_optin"
+
 /**
  * Turns on recording of skia commands in SkiaGL version of the RE. This property
  * defines number of milliseconds for the recording to take place. A non zero value

services/surfaceflinger/SurfaceFlinger.cpp

@@ -797,6 +797,12 @@ void SurfaceFlinger::bootFinished() {
     }));
 }
 
+bool shouldUseGraphiteIfCompiledAndSupported() {
+    return FlagManager::getInstance().graphite_renderengine() ||
+            (FlagManager::getInstance().graphite_renderengine_preview_rollout() &&
+             base::GetBoolProperty(PROPERTY_DEBUG_RENDERENGINE_GRAPHITE_PREVIEW_OPTIN, false));
+}
+
 void chooseRenderEngineType(renderengine::RenderEngineCreationArgs::Builder& builder) {
     char prop[PROPERTY_VALUE_MAX];
     property_get(PROPERTY_DEBUG_RENDERENGINE_BACKEND, prop, "");
@@ -825,14 +831,13 @@ void chooseRenderEngineType(renderengine::RenderEngineCreationArgs::Builder& bui
 // 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() &&
+        const bool useGraphite = shouldUseGraphiteIfCompiledAndSupported() &&
                 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.");
+        if (shouldUseGraphiteIfCompiledAndSupported()) {
+            ALOGE("RenderEngine's Graphite Skia backend was requested, but it is not compiled in "
+                  "this build! Falling back to Ganesh backend selection logic.");
         }
 #endif
         const bool useVulkan = useGraphite ||

services/surfaceflinger/common/FlagManager.cpp

@@ -115,6 +115,7 @@ void FlagManager::dump(std::string& result) const {
     DUMP_ACONFIG_FLAG(adpf_gpu_sf);
     DUMP_ACONFIG_FLAG(adpf_native_session_manager);
     DUMP_ACONFIG_FLAG(adpf_use_fmq_channel);
+    DUMP_ACONFIG_FLAG(graphite_renderengine_preview_rollout);
 
     /// Trunk stable readonly flags ///
     DUMP_ACONFIG_FLAG(adpf_fmq_sf);
@@ -265,6 +266,7 @@ FLAG_MANAGER_ACONFIG_FLAG(begone_bright_hlg, "debug.sf.begone_bright_hlg");
 FLAG_MANAGER_ACONFIG_FLAG(refresh_rate_overlay_on_external_display, "")
 FLAG_MANAGER_ACONFIG_FLAG(adpf_gpu_sf, "")
 FLAG_MANAGER_ACONFIG_FLAG(adpf_native_session_manager, "");
+FLAG_MANAGER_ACONFIG_FLAG(graphite_renderengine_preview_rollout, "");
 
 /// Trunk stable server (R/W) flags from outside SurfaceFlinger ///
 FLAG_MANAGER_ACONFIG_FLAG_IMPORTED(adpf_use_fmq_channel, "", android::os)

services/surfaceflinger/common/include/common/FlagManager.h

@@ -53,6 +53,7 @@ class FlagManager {
     bool adpf_use_fmq_channel() const;
     bool adpf_native_session_manager() const;
     bool adpf_use_fmq_channel_fixed() const;
+    bool graphite_renderengine_preview_rollout() const;
 
     /// Trunk stable readonly flags ///
     bool adpf_fmq_sf() const;

services/surfaceflinger/surfaceflinger_flags_new.aconfig

@@ -172,6 +172,13 @@ flag {
   }
 } # frame_rate_category_mrr
 
+flag {
+  name: "graphite_renderengine_preview_rollout"
+  namespace: "core_graphics"
+  description: "R/W flag to enable Skia's Graphite Vulkan backend in RenderEngine, IF it is already compiled with force_compile_graphite_renderengine, AND the debug.renderengine.graphite_preview_optin sysprop is set to true."
+  bug: "293371537"
+} # graphite_renderengine_preview_rollout
+
 flag {
   name: "latch_unsignaled_with_auto_refresh_changed"
   namespace: "core_graphics"