Revert of SK_DECLARE_STATIC_MUTEX -> static SkMutex (patchset #1 id:1 of https://codereview.chromium.org/1948193002/ )

Reason for revert:
broken the Mac and Linux builders, e.g.:

https://build.chromium.org/p/chromium/builders/Mac/builds/15151
https://build.chromium.org/p/chromium/builders/Linux%20x64/builds/19052

Original issue's description:
> SK_DECLARE_STATIC_MUTEX -> static SkMutex
>
> There's no need to use a macro to declare static SkMutexes any more
> (and there's likewise no need to restrict them to global scope).
>
> BUG=skia:
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1948193002
>
> Committed: https://skia.googlesource.com/skia/+/5e56cfd3fa1041dbb83899844fb92fa9a2ef1009

TBR=mtklein@google.com,mtklein@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review-Url: https://codereview.chromium.org/1945353003

1 files changed, 1 insertions, 1 deletions

diff --git a/tools/gpu/gl/command_buffer/GLTestContext_command_buffer.cpp b/tools/gpu/gl/command_buffer/GLTestContext_command_buffer.cpp
index a6f62f0028..850adaaf25 100644
--- a/tools/gpu/gl/command_buffer/GLTestContext_command_buffer.cpp
+++ b/tools/gpu/gl/command_buffer/GLTestContext_command_buffer.cpp
@@ -142,7 +142,7 @@ static const GrGLInterface* create_command_buffer_interface() {
 
 // We use a poor man's garbage collector of EGLDisplays. They are only
 // terminated when there are no more EGLDisplays in use. See crbug.com/603223
-static SkMutex gDisplayMutex;
+SK_DECLARE_STATIC_MUTEX(gDisplayMutex);
 static int gActiveDisplayCnt;
 SkTArray<EGLDisplay> gRetiredDisplays;