Switch several enums to enum classes

Change-Id: I00ecd0b61657196b51704f70ca31a9d1c1ac254e
diff --git a/libs/hwui/renderthread/CanvasContext.cpp b/libs/hwui/renderthread/CanvasContext.cpp
index 67c42f3..7cb7738 100644
--- a/libs/hwui/renderthread/CanvasContext.cpp
+++ b/libs/hwui/renderthread/CanvasContext.cpp
@@ -421,7 +421,7 @@
         // Make sure to release all the textures we were owning as there won't
         // be another draw
         caches.textureCache.resetMarkInUse(this);
-        caches.flush(Caches::kFlushMode_Layers);
+        caches.flush(Caches::FlushMode::Layers);
     }
 }
 
@@ -431,10 +431,10 @@
 
     ATRACE_CALL();
     if (level >= TRIM_MEMORY_COMPLETE) {
-        Caches::getInstance().flush(Caches::kFlushMode_Full);
+        Caches::getInstance().flush(Caches::FlushMode::Full);
         thread.eglManager().destroy();
     } else if (level >= TRIM_MEMORY_UI_HIDDEN) {
-        Caches::getInstance().flush(Caches::kFlushMode_Moderate);
+        Caches::getInstance().flush(Caches::FlushMode::Moderate);
     }
 }