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
Merged-In: I59330ac03c8a52b6c21a2388bba0c143e68af4cf
Bug: 265487852
Test: Presubmit, ran CtsCameraTestCases on Cuttlefish, adb shell dumpsys media camera and observed output
diff --git a/services/camera/libcameraservice/aidl/AidlCameraService.cpp b/services/camera/libcameraservice/aidl/AidlCameraService.cpp
index 4232a81..a62f6de 100644
--- a/services/camera/libcameraservice/aidl/AidlCameraService.cpp
+++ b/services/camera/libcameraservice/aidl/AidlCameraService.cpp
@@ -86,7 +86,7 @@
     if (_aidl_return == nullptr) { return fromSStatus(SStatus::ILLEGAL_ARGUMENT); }
 
     ::android::CameraMetadata cameraMetadata;
-    UStatus ret = mCameraService->getCameraCharacteristics(String16(in_cameraId.c_str()),
+    UStatus ret = mCameraService->getCameraCharacteristics(in_cameraId,
                                                            mVndkVersion,
                                                            /* overrideToPortrait= */ false,
                                                            &cameraMetadata);
@@ -140,8 +140,8 @@
     sp<hardware::camera2::ICameraDeviceCallbacks> callbacks = hybridCallbacks;
     binder::Status serviceRet = mCameraService->connectDevice(
             callbacks,
-            String16(in_cameraId.c_str()),
-            String16(""),
+            in_cameraId,
+            std::string(),
             /* clientFeatureId= */{},
             hardware::ICameraService::USE_CALLING_UID,
             /* scoreOffset= */ 0,
@@ -249,7 +249,7 @@
             [this](const hardware::CameraStatus& s) {
                 bool supportsHAL3 = false;
                 binder::Status sRet =
-                            mCameraService->supportsCameraApi(String16(s.cameraId),
+                            mCameraService->supportsCameraApi(s.cameraId,
                                     UICameraService::API_VERSION_2, &supportsHAL3);
                 return !sRet.isOk() || !supportsHAL3;
             }), cameraStatusAndIds->end());