Temporarily re-add GrContextOptions::fExplicitlyAllocateGPUResources for Fuchsia

Change-Id: I534f47cedf71cc1bdff4c9ad3cc98670228da118
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/200461
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>

include/gpu/GrContextOptions.h

@@ -144,6 +144,11 @@ struct SK_API GrContextOptions {
      */
     Enable fUseDrawInsteadOfClear = Enable::kDefault;
 
+    /**
+     * Unused but currently needed in Fuchsia
+     */
+    Enable fExplicitlyAllocateGPUResources = Enable::kYes;
+
     /**
      * Allow Ganesh to sort the opLists prior to allocating resources. This is an optional
      * behavior but, eventually, this will just be what is done and will not be optional.