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.

Bug: 265487852
Test: Presubmit, ran CtsCameraTestCases on Cuttlefish, adb shell dumpsys media camera and observed output
Change-Id: I2b258a8636030dc4b7751140db43981b39c64f0d
Merged-In: I59330ac03c8a52b6c21a2388bba0c143e68af4cf
diff --git a/services/camera/libcameraservice/utils/LatencyHistogram.h b/services/camera/libcameraservice/utils/LatencyHistogram.h
index bfd9b1b..89a9cc1 100644
--- a/services/camera/libcameraservice/utils/LatencyHistogram.h
+++ b/services/camera/libcameraservice/utils/LatencyHistogram.h
@@ -40,7 +40,7 @@
     std::vector<int64_t> mBins;
     uint64_t mTotalCount;
 
-    void formatHistogramText(String8& lineBins, String8& lineBinCounts) const;
+    void formatHistogramText(std::string& lineBins, std::string& lineBinCounts) const;
 }; // class CameraLatencyHistogram
 
 }; // namespace android