Image Capture: MediaStreamTrack::applyConstraints()

third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.cpp

Index: third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.cpp
diff --git a/third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.cpp b/third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.cpp
index 9c077a357f0561216582bd91aee69e73f1510c8f..a93e097575f7b153eadf2a430bede2cdb5fa05ec 100644
--- a/third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.cpp
+++ b/third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.cpp
@@ -27,6 +27,8 @@
 
 #include <memory>
 #include "bindings/core/v8/ExceptionMessages.h"
+#include "bindings/core/v8/ScriptPromiseResolver.h"
+#include "core/dom/DOMException.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/ExecutionContext.h"
@@ -36,6 +38,7 @@
 #include "modules/mediastream/MediaConstraintsImpl.h"
 #include "modules/mediastream/MediaStream.h"
 #include "modules/mediastream/MediaTrackCapabilities.h"
+#include "modules/mediastream/MediaTrackConstraints.h"
 #include "modules/mediastream/MediaTrackSettings.h"
 #include "modules/mediastream/UserMediaController.h"
 #include "platform/mediastream/MediaStreamCenter.h"
@@ -273,6 +276,30 @@ void MediaStreamTrack::getSettings(MediaTrackSettings& settings) {
   }
 }
 
+ScriptPromise MediaStreamTrack::applyConstraints(
+    ScriptState* scriptState,
+    const MediaTrackConstraints& constraints) {
+  ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
+  ScriptPromise promise = resolver->promise();
+
+  // |constraints| is an optional argument, which is strange.
+  // TODO(mcasas): remove this provision if |constraints| is not optional:
+  // https://github.com/w3c/mediacapture-main/issues/438
+  if (!constraints.hasAdvanced()) {
+    resolver->resolve();

[haraken, 2017/03/17 09:43:51]

Would it be better to reject with NotSupportedError?

[mcasas, 2017/03/17 15:12:47]

|constraints| is a dictionary having just one member,
|advanced| (strange, right?). The spec says that the 
|constraints| parameter is optional and doesn't specify 
what to do if it's not there. This doesn't make any sense, 
so I filed the Spec-bug in l.287, but I guessed not 
having an optional parameter is ok-ish and not a reason 
to reject().

+    return promise;
+  }
+
+  if (!m_imageCapture) {
+    resolver->reject(DOMException::create(
+        NotSupportedError, "Track type not currently supported"));
+    return promise;
+  }
+
+  m_imageCapture->setMediaTrackConstraints(resolver, constraints.advanced()[0]);
+  return promise;
+}
+
 bool MediaStreamTrack::ended() const {
   return m_stopped || (m_readyState == MediaStreamSource::ReadyStateEnded);
 }