Fully add back old GrContext flush api.

I left off the optional finished proc on the previous cl :(

Change-Id: I5f540c718bb7e12e7ea74287f1e50e35edd79700
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/209417
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Auto-Submit: Greg Daniel <egdaniel@google.com>
diff --git a/include/gpu/GrContext.h b/include/gpu/GrContext.h
index 0dd332d..45bfce1 100644
--- a/include/gpu/GrContext.h
+++ b/include/gpu/GrContext.h
@@ -263,11 +263,15 @@
      * Deprecated.
      */
     GrSemaphoresSubmitted flush(GrFlushFlags flags, int numSemaphores,
-                                GrBackendSemaphore signalSemaphores[]) {
+                                GrBackendSemaphore signalSemaphores[],
+                                GrGpuFinishedProc finishedProc = nullptr,
+                                GrGpuFinishedContext finishedContext = nullptr) {
         GrFlushInfo info;
         info.fFlags = flags;
         info.fNumSemaphores = numSemaphores;
         info.fSignalSemaphores = signalSemaphores;
+        info.fFinishedProc = finishedProc;
+        info.fFinishedContext = finishedContext;
         return this->flush(info);
     }