Use char16_t for char things.

When compiling in C++ mode, the compiler will complain about conversions
from uint16_t to char16_t. Be consistent in using char16_t for strings.

Change-Id: I052b6176ced635162920b31560052d9a64f92764
diff --git a/tools/aapt/Command.cpp b/tools/aapt/Command.cpp
index f7de558..4dc9bfc 100644
--- a/tools/aapt/Command.cpp
+++ b/tools/aapt/Command.cpp
@@ -253,7 +253,7 @@
         }
     }
     size_t len;
-    const uint16_t* str = tree.getAttributeStringValue(idx, &len);
+    const char16_t* str = tree.getAttributeStringValue(idx, &len);
     return str ? String8(str, len) : String8();
 }
 
@@ -271,7 +271,7 @@
         }
     }
     size_t len;
-    const uint16_t* str = tree.getAttributeStringValue(idx, &len);
+    const char16_t* str = tree.getAttributeStringValue(idx, &len);
     return str ? String8(str, len) : String8();
 }
 
@@ -325,7 +325,7 @@
     if (tree.getAttributeValue(idx, &value) != NO_ERROR) {
         if (value.dataType == Res_value::TYPE_STRING) {
             size_t len;
-            const uint16_t* str = tree.getAttributeStringValue(idx, &len);
+            const char16_t* str = tree.getAttributeStringValue(idx, &len);
             return str ? String8(str, len) : String8();
         }
         resTable->resolveReference(&value, 0);