media.metrics changes AString -> std::string

change from AString to std::string for how media.metrics handles
strings.  This severs the dependency on libstagefright_foundation,
where AString is implemented, so we can integrate into places
which do not want to introduce a dependency on libstagefright_foundation.

Bug: 70805723
Test: compilation/linking, CTS subset
Change-Id: I66de971b6ec354444e06112607a2d7614084cef8
diff --git a/services/mediaanalytics/MetricsSummarizer.h b/services/mediaanalytics/MetricsSummarizer.h
index a9f0786..a16c7bc 100644
--- a/services/mediaanalytics/MetricsSummarizer.h
+++ b/services/mediaanalytics/MetricsSummarizer.h
@@ -18,10 +18,10 @@
 #ifndef ANDROID_METRICSSUMMARIZER_H
 #define ANDROID_METRICSSUMMARIZER_H
 
+#include <string>
 #include <utils/threads.h>
 #include <utils/Errors.h>
 #include <utils/KeyedVector.h>
-#include <utils/String8.h>
 #include <utils/List.h>
 
 #include <media/IMediaAnalyticsService.h>
@@ -49,8 +49,8 @@
     virtual void mergeRecord(MediaAnalyticsItem &have, MediaAnalyticsItem &incoming);
 
     // dump the summarized records (for dumpsys)
-    AString dumpSummary(int &slot);
-    AString dumpSummary(int &slot, const char *only);
+    std::string dumpSummary(int &slot);
+    std::string dumpSummary(int &slot, const char *only);
 
     void setIgnorables(const char **);
     const char **getIgnorables();