Use String8/16 c_str (mainline modules)

Bug: 295394788
Test: make checkbuild
Change-Id: Ia266bccfc9100da25d8605d93c1298a341d2b11a
diff --git a/media/module/foundation/ALooperRoster.cpp b/media/module/foundation/ALooperRoster.cpp
index 4334f1e..451725d 100644
--- a/media/module/foundation/ALooperRoster.cpp
+++ b/media/module/foundation/ALooperRoster.cpp
@@ -168,7 +168,7 @@
         }
         s.append("\n");
     }
-    (void)write(fd, s.string(), s.size());
+    (void)write(fd, s.c_str(), s.size());
 }
 
 }  // namespace android
diff --git a/media/module/foundation/AString.cpp b/media/module/foundation/AString.cpp
index a5e0ff8..2f8011d 100644
--- a/media/module/foundation/AString.cpp
+++ b/media/module/foundation/AString.cpp
@@ -70,7 +70,7 @@
     : mData(NULL),
       mSize(0),
       mAllocSize(1) {
-    setTo(from.string(), from.length());
+    setTo(from.c_str(), from.length());
 }
 
 AString::AString(const AString &from)
diff --git a/media/module/foundation/MetaDataBase.cpp b/media/module/foundation/MetaDataBase.cpp
index 3370748..da383fa 100644
--- a/media/module/foundation/MetaDataBase.cpp
+++ b/media/module/foundation/MetaDataBase.cpp
@@ -434,7 +434,7 @@
         char cc[5];
         MakeFourCCString(key, cc);
         const typed_data &item = mInternalData->mItems.valueAt(i);
-        s.appendFormat("%s: %s", cc, item.asString(false).string());
+        s.appendFormat("%s: %s", cc, item.asString(false).c_str());
         if (i != 0) {
             s.append(", ");
         }
@@ -448,7 +448,7 @@
         char cc[5];
         MakeFourCCString(key, cc);
         const typed_data &item = mInternalData->mItems.valueAt(i);
-        ALOGI("%s: %s", cc, item.asString(true /* verbose */).string());
+        ALOGI("%s: %s", cc, item.asString(true /* verbose */).c_str());
     }
 }
 
diff --git a/media/module/foundation/tests/Base64_test.cpp b/media/module/foundation/tests/Base64_test.cpp
index 7a4289e..a3f93d9 100644
--- a/media/module/foundation/tests/Base64_test.cpp
+++ b/media/module/foundation/tests/Base64_test.cpp
@@ -49,7 +49,7 @@
                 paddedText.append(kBase64Padding);
             }
         }
-        sp<ABuffer> result = decodeBase64(AString(paddedText.string()));
+        sp<ABuffer> result = decodeBase64(AString(paddedText.c_str()));
 
         ASSERT_EQ(AStringUtils::Compare(expected[i].c_str(),
                 reinterpret_cast<char*>(result->data()),