AAPT2: Remove usage of u16string

For legacy reasons, we kept around the use of UTF-16 internally
in AAPT2. We don't need this and this CL removes all instances of
std::u16string and StringPiece16. The only places still needed
are when interacting with the ResTable APIs that only operate in
UTF16.

Change-Id: I492475b84bb9014fa13bf992cff447ee7a5fe588
diff --git a/tools/aapt2/xml/XmlUtil_test.cpp b/tools/aapt2/xml/XmlUtil_test.cpp
index 319e770..cbeb8bc 100644
--- a/tools/aapt2/xml/XmlUtil_test.cpp
+++ b/tools/aapt2/xml/XmlUtil_test.cpp
@@ -14,40 +14,37 @@
  * limitations under the License.
  */
 
-#include "test/Common.h"
+#include "test/Test.h"
 #include "xml/XmlUtil.h"
 
-#include <gtest/gtest.h>
-
 namespace aapt {
 
 TEST(XmlUtilTest, ExtractPackageFromNamespace) {
-    AAPT_ASSERT_FALSE(xml::extractPackageFromNamespace(u"com.android"));
-    AAPT_ASSERT_FALSE(xml::extractPackageFromNamespace(u"http://schemas.android.com/apk"));
-    AAPT_ASSERT_FALSE(xml::extractPackageFromNamespace(u"http://schemas.android.com/apk/res"));
-    AAPT_ASSERT_FALSE(xml::extractPackageFromNamespace(u"http://schemas.android.com/apk/res/"));
-    AAPT_ASSERT_FALSE(xml::extractPackageFromNamespace(
-            u"http://schemas.android.com/apk/prv/res/"));
+    AAPT_ASSERT_FALSE(xml::extractPackageFromNamespace("com.android"));
+    AAPT_ASSERT_FALSE(xml::extractPackageFromNamespace("http://schemas.android.com/apk"));
+    AAPT_ASSERT_FALSE(xml::extractPackageFromNamespace("http://schemas.android.com/apk/res"));
+    AAPT_ASSERT_FALSE(xml::extractPackageFromNamespace("http://schemas.android.com/apk/res/"));
+    AAPT_ASSERT_FALSE(xml::extractPackageFromNamespace("http://schemas.android.com/apk/prv/res/"));
 
     Maybe<xml::ExtractedPackage> p =
-            xml::extractPackageFromNamespace(u"http://schemas.android.com/apk/res/a");
+            xml::extractPackageFromNamespace("http://schemas.android.com/apk/res/a");
     AAPT_ASSERT_TRUE(p);
-    EXPECT_EQ(std::u16string(u"a"), p.value().package);
+    EXPECT_EQ(std::string("a"), p.value().package);
     EXPECT_FALSE(p.value().privateNamespace);
 
-    p = xml::extractPackageFromNamespace(u"http://schemas.android.com/apk/prv/res/android");
+    p = xml::extractPackageFromNamespace("http://schemas.android.com/apk/prv/res/android");
     AAPT_ASSERT_TRUE(p);
-    EXPECT_EQ(std::u16string(u"android"), p.value().package);
+    EXPECT_EQ(std::string("android"), p.value().package);
     EXPECT_TRUE(p.value().privateNamespace);
 
-    p = xml::extractPackageFromNamespace(u"http://schemas.android.com/apk/prv/res/com.test");
+    p = xml::extractPackageFromNamespace("http://schemas.android.com/apk/prv/res/com.test");
     AAPT_ASSERT_TRUE(p);
-    EXPECT_EQ(std::u16string(u"com.test"), p.value().package);
+    EXPECT_EQ(std::string("com.test"), p.value().package);
     EXPECT_TRUE(p.value().privateNamespace);
 
-    p = xml::extractPackageFromNamespace(u"http://schemas.android.com/apk/res-auto");
+    p = xml::extractPackageFromNamespace("http://schemas.android.com/apk/res-auto");
     AAPT_ASSERT_TRUE(p);
-    EXPECT_EQ(std::u16string(), p.value().package);
+    EXPECT_EQ(std::string(), p.value().package);
     EXPECT_TRUE(p.value().privateNamespace);
 }