Refactor Xr Depth Data to be per view

The WebXR Spec requires that a view be passed in to receive depth data.
The current implementation simply sends depth data alongside with the
rest of the frame data and process it independently in the blink
XrSession. This is fine because the current only platform that supports
depth sensing is ARCore, which only has one View. However, in order to
implement Depth Sensing for OpenXR (which has multiple views), this
needed to be changed to allow sending up data per-view. This required
refactoring the XrDepthManager to be owned by an XrViewData (since the
actual XRView objects are created per-frame and largely wrap this data).
Since XRViewData's can *theoretically* (though likely not usually done
in practice), be recreated mid session if e.g. the count/order of views
changes, this now requires storing the depth_config in XrSession to
allow for this re-creation. Rather than simply storing the depth config,
this change opts to store the entire device_config and thus remove a
few other unnecessary member variables.

As part of this update to update Depth as part of the XRViews, a few
other refactors were made, as well as some tangientially related
cleanups. A few of these arose because it seemed like it was necessary
to switch XrFrameData to be passed by value rather than const& to steal
the Views and subsequent DepthData off of it. While that turns out to
not have been necessary (because const& to a pointer doesn't prevent
stealing data from the underlying struct...), many of these changes
are left in as it improves both the overall readability and intent
behind the const& and later usage. These other changes are, in general:

* UpdateViews now handles the deferred update logic that happened
  several lines later in views(). This is more consistent with what
  a reader would likely expect from the calls.
* The UpdateViews refactor removes the need to keep the `pending_views_`
  variable. It is removed, and it's usages updated as appropriate.
* XrDepthManager is no longer exposed to XrSession, so the DepthData and
  DepthFormat strings (that the page receives off of XrSession) now live
  in XrSession.
* The Mojom XrDepthDataUpdated::time_delta member was unused outside of
  the device process, and thus is now removed from the interface.
* XrFrameProvider manually updated some additional state after calling
  `UpdatePresentationFrameState`. This state was updated regardless of
  session type, and as such was moved inside of
  `UpdatePresentationFrameState`, to facilitate std::move'ing the
  FrameData to that method. The comments around UpdateFrameState were
  also outdated/indirect and updated/clarified.
  Note that the ordering of some of these additional updates is
  different after this CL.
* XrFrameProvider stored a few variables whose storage seemed to
  now be unnecessary, these variables were removed and their usage
  was ported to closer to where they were needed.
* Because XrFrameProvider no longer needed to split off the VRPosePtr,
  from the FrameData, it was removed as a separate argument to the
  UpdatePresentationFrameState.

Bug: 342213635
Change-Id: I2fd8f3d609e955c84aff2e21b147443aeb987c02
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5565198
Reviewed-by: Brandon Jones <[email protected]>
Reviewed-by: Tom Sepez <[email protected]>
Commit-Queue: Alexander Cooper <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1307066}

Author: alcooper91

resources/chromium/webxr-test.js

@@ -1312,27 +1312,34 @@ class MockRuntime {
       return;
     }
 
+    let newDepthData;
+
     // If we don't have a current depth data, we'll return null
     // (i.e. no data is not a valid data, so it cannot be "StillValid").
     if (this.depthSensingData_ == null) {
-      frameData.depthData = null;
-      return;
+      newDepthData = null;
+    } else if(!this.depthSensingDataDirty_) {
+      newDepthData = { dataStillValid: {}};
+    } else {
+      newDepthData = {
+        updatedDepthData: {
+          timeDelta: frameData.timeDelta,
+          normTextureFromNormView: this.depthSensingData_.normDepthBufferFromNormView,
+          rawValueToMeters: this.depthSensingData_.rawValueToMeters,
+          size: { width: this.depthSensingData_.width, height: this.depthSensingData_.height },
+          pixelData: { bytes: this.depthSensingData_.depthData }
+        }
+      };
     }
 
-    if(!this.depthSensingDataDirty_) {
-      frameData.depthData = { dataStillValid: {}};
-      return;
+    for (let i = 0; i < this.primaryViews_.length; i++) {
+      this.primaryViews_[i].depthData = newDepthData;
     }
-
-    frameData.depthData = {
-      updatedDepthData: {
-        timeDelta: frameData.timeDelta,
-        normTextureFromNormView: this.depthSensingData_.normDepthBufferFromNormView,
-        rawValueToMeters: this.depthSensingData_.rawValueToMeters,
-        size: { width: this.depthSensingData_.width, height: this.depthSensingData_.height },
-        pixelData: { bytes: this.depthSensingData_.depthData }
+    if (this.enabledFeatures_.includes(xrSessionMojom.XRSessionFeature.SECONDARY_VIEWS)) {
+      for (let i = 0; i < this.secondaryViews_.length; i++) {
+        this.secondaryViews_[i].depthData = newDepthData;
       }
-    };
+    }
 
     this.depthSensingDataDirty_ = false;
   }