libutils: Remove Static.cpp and darwin hacks.

Bug: N/A
Test: in internal master, the only libraries that reference this
  symbol are:
./prebuilts/sdk/tools/linux/bin/split-select android::gDarwinIsReallyAnnoying
./prebuilts/sdk/tools/linux/bin/aapt android::gDarwinIsReallyAnnoying
./prebuilts/sdk/tools/linux/bin/aapt2 android::gDarwinIsReallyAnnoying
./prebuilts/sdk/tools/linux/lib64/libaapt2_jni.so android::gDarwinIsReallyAnnoying
./prebuilts/sdk/tools/linux/lib64/libaapt2_jni.so android::gDarwinIsReallyAnnoying
+ VNDK libraries
Test: libutils_test

Change-Id: Id39e5ef6438e48fa225ba06dbb59902ca5b60f70
diff --git a/libutils/String16.cpp b/libutils/String16.cpp
index ad335c3..84d53dd 100644
--- a/libutils/String16.cpp
+++ b/libutils/String16.cpp
@@ -24,29 +24,16 @@
 
 namespace android {
 
-static SharedBuffer* gEmptyStringBuf = NULL;
-static char16_t* gEmptyString = NULL;
+static inline char16_t* getEmptyString() {
+    static SharedBuffer* gEmptyStringBuf = [] {
+        SharedBuffer* buf = SharedBuffer::alloc(sizeof(char16_t));
+        char16_t* str = static_cast<char16_t*>(buf->data());
+        *str = 0;
+        return buf;
+    }();
 
-static inline char16_t* getEmptyString()
-{
     gEmptyStringBuf->acquire();
-   return gEmptyString;
-}
-
-void initialize_string16()
-{
-    SharedBuffer* buf = SharedBuffer::alloc(sizeof(char16_t));
-    char16_t* str = (char16_t*)buf->data();
-    *str = 0;
-    gEmptyStringBuf = buf;
-    gEmptyString = str;
-}
-
-void terminate_string16()
-{
-    SharedBuffer::bufferFromData(gEmptyString)->release();
-    gEmptyStringBuf = NULL;
-    gEmptyString = NULL;
+    return static_cast<char16_t*>(gEmptyStringBuf->data());
 }
 
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