Remove unused GrFlushFlags.

This also adds back default flush() calls which simply do a flush
without any submit.

Change-Id: Ia8c92bbdecd515d871abfa6364592f502e98656b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/298818
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
diff --git a/src/gpu/GrDrawingManager.cpp b/src/gpu/GrDrawingManager.cpp
index f61fedf..cffc136 100644
--- a/src/gpu/GrDrawingManager.cpp
+++ b/src/gpu/GrDrawingManager.cpp
@@ -200,8 +200,8 @@
 
     SkDEBUGCODE(this->validate());
 
-    if (kNone_GrFlushFlags == info.fFlags && !info.fNumSemaphores && !info.fFinishedProc &&
-            access == SkSurface::BackendSurfaceAccess::kNoAccess && !newState) {
+    if (!info.fNumSemaphores && !info.fFinishedProc &&
+        access == SkSurface::BackendSurfaceAccess::kNoAccess && !newState) {
         bool canSkip = numProxies > 0;
         for (int i = 0; i < numProxies && canSkip; ++i) {
             canSkip = !fDAG.isUsed(proxies[i]) && !this->isDDLTarget(proxies[i]);