Use DCHECK in XRRigidTransform::DecomposeMatrix

This is better than failing silently by setting position + orientation
to identity because an XRRigidTransform should never be created with a
matrix that can't be decomposed. The previous approach would result in
an invalid XRRigidTransform object since position + orientation values
wouldn't match the transformation matrix.

Bug: 969149
Change-Id: Id848a301d61e0fd9fdcab612effd0a3de27854fe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1717457
Commit-Queue: Jacob DeWitt <jacde@chromium.org>
Reviewed-by: Klaus Weidner <klausw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681104}

third_party/blink/renderer/modules/xr/xr_rigid_transform.cc

@@ -24,22 +24,18 @@ void XRRigidTransform::DecomposeMatrix() {
   // decompose matrix to position and orientation
   TransformationMatrix::DecomposedType decomposed;
   bool succeeded = matrix_->Decompose(decomposed);
-  if (succeeded) {
-    position_ =
-        DOMPointReadOnly::Create(decomposed.translate_x, decomposed.translate_y,
-                                 decomposed.translate_z, 1.0);
-
-    // TODO(https://crbug.com/929841): Minuses are needed as a workaround for
-    // bug in TransformationMatrix so that callers can still pass non-inverted
-    // quaternions.
-    orientation_ = makeNormalizedQuaternion(
-        -decomposed.quaternion_x, -decomposed.quaternion_y,
-        -decomposed.quaternion_z, decomposed.quaternion_w);
-  } else {
-    // TODO(crbug.com/969149): Is this the correct way to handle a failure here?
-    position_ = DOMPointReadOnly::Create(0.0, 0.0, 0.0, 1.0);
-    orientation_ = DOMPointReadOnly::Create(0.0, 0.0, 0.0, 1.0);
-  }
+  DCHECK(succeeded) << "Matrix decompose failed for " << matrix_->ToString();
+
+  position_ =
+      DOMPointReadOnly::Create(decomposed.translate_x, decomposed.translate_y,
+                               decomposed.translate_z, 1.0);
+
+  // TODO(https://crbug.com/929841): Minuses are needed as a workaround for
+  // bug in TransformationMatrix so that callers can still pass non-inverted
+  // quaternions.
+  orientation_ = makeNormalizedQuaternion(
+      -decomposed.quaternion_x, -decomposed.quaternion_y,
+      -decomposed.quaternion_z, decomposed.quaternion_w);
 }
 
 XRRigidTransform::XRRigidTransform(DOMPointInit* position,