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
diff --git a/src/ports/SkFontConfigInterface_direct.cpp b/src/ports/SkFontConfigInterface_direct.cpp
index f236002..d6fa96a 100644
--- a/src/ports/SkFontConfigInterface_direct.cpp
+++ b/src/ports/SkFontConfigInterface_direct.cpp
@@ -32,7 +32,7 @@
 
 // Fontconfig is not threadsafe before 2.10.91. Before that, we lock with a global mutex.
 // See https://bug.skia.org/1497 for background.
-static SkMutex gFCMutex;
+SK_DECLARE_STATIC_MUTEX(gFCMutex);
 
 #ifdef SK_DEBUG
 void* CreateThreadFcLocked() { return new bool(false); }
diff --git a/src/ports/SkFontHost_FreeType.cpp b/src/ports/SkFontHost_FreeType.cpp
index 1cde6cb..b53364e 100644
--- a/src/ports/SkFontHost_FreeType.cpp
+++ b/src/ports/SkFontHost_FreeType.cpp
@@ -145,7 +145,7 @@
 
 struct SkFaceRec;
 
-static SkMutex gFTMutex;
+SK_DECLARE_STATIC_MUTEX(gFTMutex);
 static FreeTypeLibrary* gFTLibrary;
 static SkFaceRec* gFaceRecHead;
 
diff --git a/src/ports/SkFontHost_fontconfig.cpp b/src/ports/SkFontHost_fontconfig.cpp
index 416173a..0ffc261 100644
--- a/src/ports/SkFontHost_fontconfig.cpp
+++ b/src/ports/SkFontHost_fontconfig.cpp
@@ -10,7 +10,7 @@
 #include "SkMutex.h"
 #include "SkRefCnt.h"
 
-static SkMutex gFontConfigInterfaceMutex;
+SK_DECLARE_STATIC_MUTEX(gFontConfigInterfaceMutex);
 static SkFontConfigInterface* gFontConfigInterface;
 
 SkFontConfigInterface* SkFontConfigInterface::RefGlobal() {
diff --git a/src/ports/SkFontHost_mac.cpp b/src/ports/SkFontHost_mac.cpp
index 6f0bbad..8593b39 100644
--- a/src/ports/SkFontHost_mac.cpp
+++ b/src/ports/SkFontHost_mac.cpp
@@ -54,7 +54,7 @@
 #define USE_GLOBAL_MUTEX_FOR_CG_ACCESS
 
 #ifdef USE_GLOBAL_MUTEX_FOR_CG_ACCESS
-    static SkMutex gCGMutex;
+    SK_DECLARE_STATIC_MUTEX(gCGMutex);
     #define AUTO_CG_LOCK()  SkAutoMutexAcquire amc(gCGMutex)
 #else
     #define AUTO_CG_LOCK()
@@ -550,7 +550,7 @@
     return face;
 }
 
-static SkMutex gGetDefaultFaceMutex;
+SK_DECLARE_STATIC_MUTEX(gGetDefaultFaceMutex);
 static SkTypeface* GetDefaultFace() {
     SkAutoMutexAcquire ma(gGetDefaultFaceMutex);
 
diff --git a/src/ports/SkFontMgr_fontconfig.cpp b/src/ports/SkFontMgr_fontconfig.cpp
index 32f10a4..610a300 100644
--- a/src/ports/SkFontMgr_fontconfig.cpp
+++ b/src/ports/SkFontMgr_fontconfig.cpp
@@ -62,7 +62,7 @@
 
 // Fontconfig is not threadsafe before 2.10.91. Before that, we lock with a global mutex.
 // See https://bug.skia.org/1497 for background.
-static SkMutex gFCMutex;
+SK_DECLARE_STATIC_MUTEX(gFCMutex);
 
 #ifdef SK_DEBUG
 void* CreateThreadFcLocked() { return new bool(false); }
diff --git a/src/ports/SkTLS_win.cpp b/src/ports/SkTLS_win.cpp
index 3f00842..8bc55a0 100644
--- a/src/ports/SkTLS_win.cpp
+++ b/src/ports/SkTLS_win.cpp
@@ -12,7 +12,7 @@
 
 static bool gOnce = false;
 static DWORD gTlsIndex;
-static SkMutex gMutex;
+SK_DECLARE_STATIC_MUTEX(gMutex);
 
 void* SkTLS::PlatformGetSpecific(bool forceCreateTheSlot) {
     if (!forceCreateTheSlot && !gOnce) {