[Touchless] Disable Overscroll

Unneeded without touch.

Bug: 986559
Change-Id: I9243f915924cc36e304ce5e864c708b5045638ec
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1717264
Auto-Submit: David Bokan <bokan@chromium.org>
Commit-Queue: Ken Buchanan <kenrb@chromium.org>
Reviewed-by: Ken Buchanan <kenrb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#680594}

content/browser/BUILD.gn

@@ -2498,9 +2498,13 @@ jumbo_source_set("browser") {
     ]
     libs += [ "jnigraphics" ]
 
-    # TODO(crbug.com/986346): this define should not be required once debug URL
-    # triggering has been generalized.
-    if (!notouch_build) {
+    if (notouch_build) {
+      # Similar to the bug below, there should be an API to let the embedder
+      # control this.
+      defines += [ "DISABLE_OVERSCROLL" ]
+    } else {
+      # TODO(crbug.com/986346): this define should not be required once debug URL
+      # triggering has been generalized.
       defines += [ "ENABLE_ADDRESS_BAR" ]
     }
   } else {

content/browser/renderer_host/render_widget_host_view_android.cc

@@ -2463,6 +2463,9 @@ void RenderWidgetHostViewAndroid::ComputeEventLatencyOSTouchHistograms(
 }
 
 void RenderWidgetHostViewAndroid::CreateOverscrollControllerIfPossible() {
+#if defined(DISABLE_OVERSCROLL)
+  return;
+#else
   // an OverscrollController is already set
   if (overscroll_controller_)
     return;
@@ -2498,6 +2501,7 @@ void RenderWidgetHostViewAndroid::CreateOverscrollControllerIfPossible() {
 
   overscroll_controller_ = std::make_unique<OverscrollControllerAndroid>(
       overscroll_refresh_handler, compositor, view_.GetDipScale());
+#endif
 }
 
 void RenderWidgetHostViewAndroid::SetOverscrollControllerForTesting(