Ozone caca: Fix segfault during GPU initialization

ui/ozone/platform/caca/ozone_platform_caca.cc

Index: ui/ozone/platform/caca/ozone_platform_caca.cc
diff --git a/ui/ozone/platform/caca/ozone_platform_caca.cc b/ui/ozone/platform/caca/ozone_platform_caca.cc
index 53fab1b0c8bbf319a22c8123e1df6a3a415e1e5d..536a6d29ba2c696f0b06a7f87f45f0c479f92a8f 100644
--- a/ui/ozone/platform/caca/ozone_platform_caca.cc
+++ b/ui/ozone/platform/caca/ozone_platform_caca.cc
@@ -73,6 +73,12 @@ class OzonePlatformCaca : public OzonePlatform {
   }
 
   void InitializeGPU() override {
+    if (!window_manager_) {
+      // The return value of GetSurfaceFactoryOzone() must be non-null so a
+      // dummy instance of CacaWindowManager is needed to make the GPU
+      // initialization gracefully fail.
+      window_manager_.reset(new CacaWindowManager);
+    }
   }
 
  private: