Hide location bar on WebKit programmatic scroll.

content/renderer/render_widget.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/render_widget.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
@@ skipping 1463 matching lines @@
     return;
 
   did_show_ = true;
   // NOTE: initial_pos_ may still have its default values at this point, but
   // that's okay.  It'll be ignored if as_popup is false, or the browser
   // process will impose a default position otherwise.
   Send(new ViewHostMsg_ShowWidget(opener_id_, routing_id_, initial_pos_));
   SetPendingWindowRect(initial_pos_);
 }
 
+void RenderWidget::hideTopControls() {
+  if (!compositor_)

[jamesr, 2013/03/04 21:44:03]

Do you expect this case to be hit?  Why?

[John Knottenbelt, 2013/03/05 16:41:48]

It seems that all method invocations on compositor_ in this file are guarded by
a NULL check.

I would expect that for Chrome on Android, compositor_ would be non-null, as the
call to hideTopControls originates from a WebKit scroll, and I believe that the
compositor_ should already have been set up by then.

For platforms that are not use accelerated compositing, or have it disabled due
to a switch, the compositor_ will be NULL. hideTopControls() method is public on
RenderWidget, so it could still be called from WebKit.

+    return;
+
+  compositor_->layer_tree_host()->hideTopControls();
+}
+
 void RenderWidget::didFocus() {
 }
 
 void RenderWidget::didBlur() {
 }
 
 void RenderWidget::DoDeferredClose() {
   Send(new ViewHostMsg_Close(routing_id_));
 }
 
@@ skipping 648 matching lines @@
 bool RenderWidget::WillHandleGestureEvent(
     const WebKit::WebGestureEvent& event) {
   return false;
 }
 
 bool RenderWidget::HasTouchEventHandlersAt(const gfx::Point& point) const {
   return true;
 }
 
 }  // namespace content