Grant independence to SkBaseMutex on Windows.

src/ports/SkMutex_win.h

Index: src/ports/SkMutex_win.h
diff --git a/src/ports/SkMutex_win.h b/src/ports/SkMutex_win.h
index d12fd033f3d6d6a457d1b9022987572f8be9690f..745a3e33d6ee96009facbdb13f4c4bf5f2eaa808 100644
--- a/src/ports/SkMutex_win.h
+++ b/src/ports/SkMutex_win.h
@@ -31,8 +31,14 @@
 #endif
 
 // On Windows, SkBaseMutex and SkMutex are the same thing,
-// we can't easily get rid of static initializers.
-class SkMutex {
+// we can't easily get rid of static initializers. However,
+// we preserve the same inheritance pattern as other platforms
+// so that we can forward-declare cleanly.
+struct SkBaseMutex {

[mtklein, 2014/06/30 22:24:01]

Don't you have to do it the other way around?  SkBaseMutex has now lost its
acquire() and release() methods, among other things.

struct SkBaseMutex {
  ... real implementation ...
};
class SkMutex : public SkBaseMutex {};

ought to work?

+
+};
+
+class SkMutex : public SkBaseMutex {
 public:
     SkMutex() {
         InitializeCriticalSection(&fStorage);
@@ -67,8 +73,6 @@ private:
     SkDEBUGCODE(DWORD fOwner;)
 };
 
-typedef SkMutex SkBaseMutex;
-
 // Windows currently provides no documented means of POD initializing a CRITICAL_SECTION.
 #define SK_DECLARE_STATIC_MUTEX(name) static SkBaseMutex name
 #define SK_DECLARE_GLOBAL_MUTEX(name) SkBaseMutex name