Switch blink::ComputeCapabilitiesForVideoSource() away from WebString

... and use WTF::String instead.

BUG=704136
R=guidou@chromium.org

Change-Id: Ic82e4a3926d17f3cd0207695b9ccb290aa248080
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2303674
Commit-Queue: Antonio Gomes <tonikitoo@igalia.com>
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Cr-Commit-Position: refs/heads/master@{#789621}

third_party/blink/renderer/modules/mediastream/media_stream_constraints_util.cc

@@ -283,7 +283,7 @@ double StringConstraintFitnessDistance(const WebString& value,
 }
 
 MediaStreamSource::Capabilities ComputeCapabilitiesForVideoSource(
-    const WebString& device_id,
+    const String& device_id,
     const media::VideoCaptureFormats& formats,
     media::VideoFacingMode facing_mode,
     bool is_device_capture,
@@ -293,7 +293,7 @@ MediaStreamSource::Capabilities ComputeCapabilitiesForVideoSource(
   if (is_device_capture) {
     capabilities.facing_mode = ToPlatformFacingMode(facing_mode);
     if (group_id)
-      capabilities.group_id = WebString::FromUTF8(*group_id);
+      capabilities.group_id = String::FromUTF8(*group_id);
   }
   if (!formats.empty()) {
     int max_width = 1;

third_party/blink/renderer/modules/mediastream/media_stream_constraints_util.h

@@ -15,6 +15,7 @@
 #include "third_party/blink/renderer/platform/mediastream/media_constraints.h"
 #include "third_party/blink/renderer/platform/mediastream/media_stream_audio_processor_options.h"
 #include "third_party/blink/renderer/platform/mediastream/media_stream_source.h"
+#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
 
 namespace blink {
 
@@ -336,7 +337,7 @@ double StringConstraintFitnessDistance(
 // |formats|. |facing_mode| is valid only in case of video device capture.
 MODULES_EXPORT MediaStreamSource::Capabilities
 ComputeCapabilitiesForVideoSource(
-    const blink::WebString& device_id,
+    const String& device_id,
     const media::VideoCaptureFormats& formats,
     media::VideoFacingMode facing_mode,
     bool is_device_capture,

third_party/blink/renderer/modules/mediastream/user_media_processor.cc

@@ -1215,8 +1215,8 @@ MediaStreamSource* UserMediaProcessor::InitializeVideoSourceObject(
     String device_id(device.id.data());
     source->SetCapabilities(ComputeCapabilitiesForVideoSource(
         // TODO(crbug.com/704136): Change ComputeCapabilitiesForVideoSource to
-        // operate over WTF::Vector and WTF::String.
-        blink::WebString::FromUTF8(device.id),
+        // operate over WTF::Vector.
+        String::FromUTF8(device.id),
         ToStdVector(*current_request_info_->GetNativeVideoFormats(device_id)),
         device.video_facing, current_request_info_->is_video_device_capture(),
         device.group_id));