Use String8/16 c_str [drm]

Bug: 295394788
Test: make checkbuild
Change-Id: I8446de3a553a3ddce2da5c4551127039638e0a98
diff --git a/drm/1.0/default/DrmPlugin.cpp b/drm/1.0/default/DrmPlugin.cpp
index 809f694..dfa5d22 100644
--- a/drm/1.0/default/DrmPlugin.cpp
+++ b/drm/1.0/default/DrmPlugin.cpp
@@ -98,8 +98,7 @@
                 break;
             }
         }
-        _hidl_cb(toStatus(status), toHidlVec(legacyRequest), requestType,
-                 defaultUrl.string());
+        _hidl_cb(toStatus(status), toHidlVec(legacyRequest), requestType, defaultUrl.c_str());
         return Void();
     }
 
@@ -219,7 +218,7 @@
         String8 legacyValue;
         status_t status = mLegacyPlugin->getPropertyString(
                 String8(propertyName.c_str()), legacyValue);
-        _hidl_cb(toStatus(status), legacyValue.string());
+        _hidl_cb(toStatus(status), legacyValue.c_str());
         return Void();
     }
 
diff --git a/drm/1.0/default/SharedLibrary.cpp b/drm/1.0/default/SharedLibrary.cpp
index 0a942cd..c9b5389 100644
--- a/drm/1.0/default/SharedLibrary.cpp
+++ b/drm/1.0/default/SharedLibrary.cpp
@@ -26,7 +26,7 @@
 namespace helper {
 
 SharedLibrary::SharedLibrary(const String8& path) {
-    mLibHandle = dlopen(path.string(), RTLD_NOW);
+    mLibHandle = dlopen(path.c_str(), RTLD_NOW);
 }
 
 SharedLibrary::~SharedLibrary() {
diff --git a/drm/1.0/default/include/PluginLoader.h b/drm/1.0/default/include/PluginLoader.h
index 0c45fb3..e243f42 100644
--- a/drm/1.0/default/include/PluginLoader.h
+++ b/drm/1.0/default/include/PluginLoader.h
@@ -39,9 +39,9 @@
          */
         String8 pluginDir(dir);
 
-        DIR* pDir = opendir(pluginDir.string());
+        DIR* pDir = opendir(pluginDir.c_str());
         if (pDir == NULL) {
-            ALOGE("Failed to find plugin directory %s", pluginDir.string());
+            ALOGE("Failed to find plugin directory %s", pluginDir.c_str());
         } else {
             struct dirent* pEntry;
             while ((pEntry = readdir(pDir))) {