[vr] Prevent mouse move events while clicking.

- Relands fix of https://codereview.chromium.org/2944453002.

Bug: 741020
Change-Id: Id6cb772edd0509afa60c217be02188bf16fcada9
Reviewed-on: https://chromium-review.googlesource.com/567384Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Commit-Queue: Tibor Goldschwendt <tiborg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#485956}

chrome/browser/android/vr_shell/vr_shell_gl.cc

@@ -636,6 +636,12 @@ void VrShellGl::OnContentLeave() {
 }
 
 void VrShellGl::OnContentMove(const gfx::PointF& normalized_hit_point) {
+  // TODO(mthiesse, vollick): Content is currently way too sensitive to mouse
+  // moves for how noisy the controller is. It's almost impossible to click a
+  // link without unintentionally starting a drag event. For this reason we
+  // disable mouse moves, only delivering a down and up event.
+  if (controller_->ButtonState(gvr::kControllerButtonClick))
+    return;
   SendGestureToContent(
       MakeMouseEvent(blink::WebInputEvent::kMouseMove, normalized_hit_point));
 }