cameraservice: Migrate all internal String8/String16s to std::string

String8 and String16 are deprecated classes. It is recommended to use
std::string or std::u16string wherever possible. String16 is the native
string class for aidl, but Strings marked @utf8InCpp can use std::string
directly.

This patch standardizes libcameraservice's use of strings to
std::string, which is capable of storing utf-8 strings. This makes the
code more readable and potentially reduces the number of string copies
to a minimum.

A new set of string utils is added to frameworks/av/camera to aid this
migration.

Change-Id: I7aee6696f149244c643ec1399815155f3f562538
Merged-In: I7aee6696f149244c643ec1399815155f3f562538
Bug: 265487852
Test: Presubmit, ran CtsCameraTestCases on Cuttlefish, adb shell dumpsys media camera and observed output
(cherry picked from commit b56b7e54b60ca930a44ea10e46e3ca1e1c714a5b)
diff --git a/core/jni/android_hardware_Camera.cpp b/core/jni/android_hardware_Camera.cpp
index 2a670e8..1c59742 100644
--- a/core/jni/android_hardware_Camera.cpp
+++ b/core/jni/android_hardware_Camera.cpp
@@ -17,22 +17,21 @@
 
 //#define LOG_NDEBUG 0
 #define LOG_TAG "Camera-JNI"
-#include <utils/Log.h>
-
-#include "jni.h"
-#include <nativehelper/JNIHelp.h>
-#include "core_jni_helpers.h"
 #include <android_runtime/android_graphics_SurfaceTexture.h>
 #include <android_runtime/android_view_Surface.h>
-
+#include <binder/IMemory.h>
+#include <camera/Camera.h>
+#include <camera/StringUtils.h>
 #include <cutils/properties.h>
-#include <utils/Vector.h>
-#include <utils/Errors.h>
-
 #include <gui/GLConsumer.h>
 #include <gui/Surface.h>
-#include <camera/Camera.h>
-#include <binder/IMemory.h>
+#include <nativehelper/JNIHelp.h>
+#include <utils/Errors.h>
+#include <utils/Log.h>
+#include <utils/Vector.h>
+
+#include "core_jni_helpers.h"
+#include "jni.h"
 
 using namespace android;
 
@@ -562,7 +561,7 @@
     const char16_t *rawClientName = reinterpret_cast<const char16_t*>(
         env->GetStringChars(clientPackageName, NULL));
     jsize rawClientNameLen = env->GetStringLength(clientPackageName);
-    String16 clientName(rawClientName, rawClientNameLen);
+    std::string clientName = toStdString(rawClientName, rawClientNameLen);
     env->ReleaseStringChars(clientPackageName,
                             reinterpret_cast<const jchar*>(rawClientName));