Ensure font is loaded by PHASE_SYSTEM_SERVICES_READY

This is needed to fix the corner cases where system_server tries to draw
some text before FontManagerService is initialized.

Bug: 327941215
Test: successful boot
Change-Id: Iee21f13112681fa43fb08828d27dfe34d2e58b41

2 files changed, 18 insertions, 1 deletions

diff --git a/core/java/android/text/flags/flags.aconfig b/core/java/android/text/flags/flags.aconfig
index 559fa96d0198..44fa1863afc1 100644
--- a/core/java/android/text/flags/flags.aconfig
+++ b/core/java/android/text/flags/flags.aconfig
@@ -53,6 +53,19 @@ flag {
 }
 
 flag {
+  name: "complete_font_load_in_system_services_ready"
+  namespace: "text"
+  description: "Fix to ensure that font loading is complete on system-services-ready boot phase."
+  # Make read only, as font loading is in the critical boot path which happens before the read-write
+  # flags propagate to the device.
+  is_fixed_read_only: true
+  bug: "327941215"
+  metadata {
+    purpose: PURPOSE_BUGFIX
+  }
+}
+
+flag {
   name: "phrase_strict_fallback"
   namespace: "text"
   description: "Feature flag for automatic fallback from phrase based line break to strict line break."
diff --git a/services/core/java/com/android/server/graphics/fonts/FontManagerService.java b/services/core/java/com/android/server/graphics/fonts/FontManagerService.java
index 7b844a099841..f3836794c32e 100644
--- a/services/core/java/com/android/server/graphics/fonts/FontManagerService.java
+++ b/services/core/java/com/android/server/graphics/fonts/FontManagerService.java
@@ -165,7 +165,11 @@ public final class FontManagerService extends IFontManager.Stub {
 
         @Override
         public void onBootPhase(int phase) {
-            if (phase == SystemService.PHASE_ACTIVITY_MANAGER_READY) {
+            final int latestFontLoadBootPhase =
+                    (Flags.completeFontLoadInSystemServicesReady())
+                            ? SystemService.PHASE_SYSTEM_SERVICES_READY
+                            : SystemService.PHASE_ACTIVITY_MANAGER_READY;
+            if (phase == latestFontLoadBootPhase) {
                 // Wait for FontManagerService to start since it will be needed after this point.
                 mServiceStarted.join();
             }