SF: Use std::string for display name

Bug: 74619554
Test: Build
Change-Id: Ic07b38516233dda0c275774ccca315b1ac205d47
diff --git a/services/surfaceflinger/DisplayDevice.cpp b/services/surfaceflinger/DisplayDevice.cpp
index 7c6302e..33e57cd 100644
--- a/services/surfaceflinger/DisplayDevice.cpp
+++ b/services/surfaceflinger/DisplayDevice.cpp
@@ -149,8 +149,8 @@
     return mDisplayHeight;
 }
 
-void DisplayDevice::setDisplayName(const String8& displayName) {
-    if (!displayName.isEmpty()) {
+void DisplayDevice::setDisplayName(const std::string& displayName) {
+    if (!displayName.empty()) {
         // never override the name with an empty name
         mDisplayName = displayName;
     }
@@ -201,8 +201,7 @@
 
     status_t result = mDisplaySurface->advanceFrame();
     if (result != NO_ERROR) {
-        ALOGE("[%s] failed pushing new frame to HWC: %d",
-                mDisplayName.string(), result);
+        ALOGE("[%s] failed pushing new frame to HWC: %d", mDisplayName.c_str(), result);
     }
 }
 
@@ -481,7 +480,7 @@
 void DisplayDevice::dump(String8& result) const {
     const Transform& tr(mGlobalTransform);
     ANativeWindow* const window = mNativeWindow.get();
-    result.appendFormat("+ DisplayDevice: %s\n", mDisplayName.string());
+    result.appendFormat("+ DisplayDevice: %s\n", mDisplayName.c_str());
     result.appendFormat("   type=%x, hwcId=%d, layerStack=%u, (%4dx%4d), ANativeWindow=%p "
                         "(%d:%d:%d:%d), orient=%2d (type=%08x), "
                         "flips=%u, isSecure=%d, powerMode=%d, activeConfig=%d, numLayers=%zu\n",