Revert of Remove SkThread.h, include SkMutex.h or SkAtomics.h as appropriate.

src/core/SkBitmapHeap.h

Index: src/core/SkBitmapHeap.h
diff --git a/src/core/SkBitmapHeap.h b/src/core/SkBitmapHeap.h
index 259d947923bf8524d253c38538d8303a0ee35172..07f629c77ae7731e920ee6e88d356b3bc60f0cf1 100644
--- a/src/core/SkBitmapHeap.h
+++ b/src/core/SkBitmapHeap.h
@@ -12,7 +12,7 @@
 #include "SkFlattenable.h"
 #include "SkRefCnt.h"
 #include "SkTDArray.h"
-#include "SkAtomics.h"
+#include "SkThread.h"
 
 /**
  * SkBitmapHeapEntry provides users of SkBitmapHeap (using internal storage) with a means to...
@@ -52,7 +52,7 @@
 
 class SkBitmapHeapReader : public SkRefCnt {
 public:
-
+    
 
     SkBitmapHeapReader() : INHERITED() {}
     virtual SkBitmap* getBitmap(int32_t slot) const = 0;
@@ -69,7 +69,7 @@
 public:
     class ExternalStorage : public SkRefCnt {
      public:
-
+        
 
         virtual bool insert(const SkBitmap& bitmap, int32_t slot) = 0;