[LibWebRTC] Build fails with clang on Linux

https://bugs.webkit.org/show_bug.cgi?id=269707

Reviewed by Youenn Fablet.

Remove duplicate fromStdString() implementations.

* Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCCertificateGenerator.cpp:
(WebCore::LibWebRTCCertificateGenerator::fromStdString): Deleted.
* Source/WebCore/platform/mediastream/libwebrtc/LibWebRTCProvider.cpp:
(WebCore::fromStdString): Deleted.

Canonical link: https://commits.webkit.org/274980@main

Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCCertificateGenerator.cpp

@@ -29,6 +29,7 @@
 
 #include "LibWebRTCMacros.h"
 #include "LibWebRTCProvider.h"
+#include "LibWebRTCUtils.h"
 #include "RTCCertificate.h"
 
 ALLOW_UNUSED_PARAMETERS_BEGIN
@@ -45,11 +46,6 @@ namespace WebCore {
 
 namespace LibWebRTCCertificateGenerator {
 
-static inline String fromStdString(const std::string& value)
-{
-    return String::fromUTF8(value.data(), value.length());
-}
-
 class RTCCertificateGeneratorCallbackWrapper : public ThreadSafeRefCounted<RTCCertificateGeneratorCallbackWrapper, WTF::DestructionThread::Main> {
 public:
     static Ref<RTCCertificateGeneratorCallbackWrapper> create(Ref<SecurityOrigin>&& origin, Function<void(ExceptionOr<Ref<RTCCertificate>>&&)>&& resultCallback)

Source/WebCore/platform/mediastream/libwebrtc/LibWebRTCProvider.cpp

@@ -30,6 +30,7 @@
 
 #include "ContentType.h"
 #include "LibWebRTCAudioModule.h"
+#include "LibWebRTCUtils.h"
 #include "Logging.h"
 #include "MediaCapabilitiesDecodingInfo.h"
 #include "MediaCapabilitiesEncodingInfo.h"
@@ -426,11 +427,6 @@ static inline std::optional<cricket::MediaType> typeFromKind(const String& kind)
     return { };
 }
 
-static inline String fromStdString(const std::string& value)
-{
-    return String::fromUTF8(value.data(), value.length());
-}
-
 static inline std::optional<uint16_t> toChannels(absl::optional<int> numChannels)
 {
     if (!numChannels)