Increase Metal pipeline state cache size to 1024 entries

The cache size is now configurable by the client. This CL re-implements
the change made here:

https://skia.googlesource.com/skia/+/450ba0a2b25de433470d5bfa2f21a0db833786fc

Bug: chromium:974219
Bug: chromium:988964
Change-Id: Ibef0f842c30154d7295909284c5dc6922c3fa40a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1790501
Commit-Queue: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: ccameron <ccameron@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Victor Miura <vmiura@chromium.org>
Cr-Commit-Position: refs/heads/master@{#694887}

gpu/command_buffer/service/shared_context_state.cc

@@ -149,6 +149,9 @@ void SharedContextState::InitializeGrContext(
     // in GetCapabilities and ensuring these are also used by the
     // PaintOpBufferSerializer.
     GrContextOptions options;
+    if (GrContextIsMetal()) {
+      options.fRuntimeProgramCacheSize = 1024;
+    }
     options.fDriverBugWorkarounds =
         GrDriverBugWorkarounds(workarounds.ToIntSet());
     options.fDisableCoverageCountingPaths = true;