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: I59330ac03c8a52b6c21a2388bba0c143e68af4cf
Bug: 265487852
Test: Presubmit, ran CtsCameraTestCases on Cuttlefish, adb shell dumpsys media camera and observed output
diff --git a/services/camera/libcameraservice/common/Camera2ClientBase.h b/services/camera/libcameraservice/common/Camera2ClientBase.h
index 5cf3033..30c763d 100644
--- a/services/camera/libcameraservice/common/Camera2ClientBase.h
+++ b/services/camera/libcameraservice/common/Camera2ClientBase.h
@@ -50,10 +50,10 @@
     Camera2ClientBase(const sp<CameraService>& cameraService,
                       const sp<TCamCallbacks>& remoteCallback,
                       std::shared_ptr<CameraServiceProxyWrapper> cameraServiceProxyWrapper,
-                      const String16& clientPackageName,
+                      const std::string& clientPackageName,
                       bool systemNativeClient,
-                      const std::optional<String16>& clientFeatureId,
-                      const String8& cameraId,
+                      const std::optional<std::string>& clientFeatureId,
+                      const std::string& cameraId,
                       int api1CameraId,
                       int cameraFacing,
                       int sensorOrientation,
@@ -65,11 +65,12 @@
                       bool legacyClient = false);
     virtual ~Camera2ClientBase();
 
-    virtual status_t      initialize(sp<CameraProviderManager> manager, const String8& monitorTags);
-    virtual status_t      dumpClient(int fd, const Vector<String16>& args);
-    virtual status_t      startWatchingTags(const String8 &tags, int out);
-    virtual status_t      stopWatchingTags(int out);
-    virtual status_t      dumpWatchedEventsToVector(std::vector<std::string> &out);
+    virtual status_t      initialize(sp<CameraProviderManager> manager,
+            const std::string& monitorTags) override;
+    virtual status_t      dumpClient(int fd, const Vector<String16>& args) override;
+    virtual status_t      startWatchingTags(const std::string &tags, int out) override;
+    virtual status_t      stopWatchingTags(int out) override;
+    virtual status_t      dumpWatchedEventsToVector(std::vector<std::string> &out) override;
 
     /**
      * NotificationListener implementation
@@ -130,7 +131,7 @@
         mutable Mutex mRemoteCallbackLock;
     } mSharedCameraCallbacks;
 
-    status_t      injectCamera(const String8& injectedCamId,
+    status_t      injectCamera(const std::string& injectedCamId,
                                sp<CameraProviderManager> manager) override;
     status_t      stopInjection() override;
 
@@ -181,7 +182,7 @@
 
 private:
     template<typename TProviderPtr>
-    status_t              initializeImpl(TProviderPtr providerPtr, const String8& monitorTags);
+    status_t              initializeImpl(TProviderPtr providerPtr, const std::string& monitorTags);
 
     binder::Status disconnectImpl();