WebVR: Defer GetVSync calls until the current frame is submitted.

third_party/WebKit/LayoutTests/vr/resources/mock-vr-service.js

Index: third_party/WebKit/LayoutTests/vr/resources/mock-vr-service.js
diff --git a/third_party/WebKit/LayoutTests/vr/resources/mock-vr-service.js b/third_party/WebKit/LayoutTests/vr/resources/mock-vr-service.js
index 53806a08cc9c733285ea14094fd57ceddf4a2625..3cd6c53c6ab0ff76d5777557ab12fd410f1830c4 100644
--- a/third_party/WebKit/LayoutTests/vr/resources/mock-vr-service.js
+++ b/third_party/WebKit/LayoutTests/vr/resources/mock-vr-service.js
@@ -24,10 +24,18 @@ let mockVRService = loadMojoModules(
       }
     }
 
-    requestPresent(secureOrigin) {
+    requestPresent(secureOrigin, submitFrameClient) {
+      // console.log("requestPresent");

[mthiesse, 2017/05/18 23:39:14]

nit: remove commented out log statements here and below.

[klausw, 2017/05/19 04:06:47]

Done.

+      this.submitFrameClient_ = submitFrameClient;
       return Promise.resolve({success: true});
     }
 
+    submitFrame(frameId, mailboxHolder) {
+      // console.log("submitFrame frameId=" + frameId);
+      this.submitFrameClient_.onSubmitFrameTransferred();
+      this.submitFrameClient_.onSubmitFrameRendered();
+    }
+
     setPose(pose) {
       if (pose == null) {
         this.vsync_provider_.pose_ = null;
@@ -37,7 +45,9 @@ let mockVRService = loadMojoModules(
       }
     }
 
-    getVRVSyncProvider(request) { this.vsync_provider_.bind(request); }
+    getVRVSyncProvider(request) {
+      this.vsync_provider_.bind(request);
+    }
 
     forceActivate(reason) {
       this.displayClient_.onActivate(reason);
@@ -66,6 +76,7 @@ let mockVRService = loadMojoModules(
       this.binding_.bind(request);
     }
     getVSync() {
+      // console.log("getVSync timeDelta=" + this.timeDelta_);
       if (this.pose_) {
         this.pose_.poseIndex++;
       }