[Android] Disable the touch ack timeout on mobile sites

content/browser/renderer_host/render_widget_host_impl.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/browser/renderer_host/render_widget_host_impl.h"
 
 #include <math.h>
 #include <set>
 #include <utility>
 
@@ skipping 83 matching lines @@
 // returning a null or incorrectly sized backing-store from GetBackingStore.
 // This timeout impacts the "choppiness" of our window resize perf.
 const int kPaintMsgTimeoutMS = 50;
 
 typedef std::pair<int32, int32> RenderWidgetHostID;
 typedef base::hash_map<RenderWidgetHostID, RenderWidgetHostImpl*>
     RoutingIDWidgetMap;
 base::LazyInstance<RoutingIDWidgetMap> g_routing_id_widget_map =
     LAZY_INSTANCE_INITIALIZER;
 
+int GetInputRouterViewFlagsFromCompositorFrameMetadata(
+    const cc::CompositorFrameMetadata metadata) {
+  int view_flags = InputRouter::VIEW_FLAGS_NONE;
+
+  if (metadata.min_page_scale_factor == metadata.max_page_scale_factor)
+    view_flags |= InputRouter::FIXED_PAGE_SCALE;
+
+  float window_width_dip =
+      metadata.page_scale_factor * metadata.viewport_size.width();
+  if (metadata.root_layer_size.width() <= window_width_dip)

[Xianzhu, 2014/01/14 21:54:19]

Can we simply skip timeout for all pages with viewport tag?

[jdduke (slow), 2014/01/14 21:56:38]

Where do we get that data?

[Xianzhu, 2014/01/14 23:56:18]

My fault. I thought it is available in the metadata.

[johnme, 2014/01/15 02:15:09]

No, many desktop sites have viewport tags like <meta name="viewport"
content="width=1024"> (including, say, theverge.com) and we shouldn't treat
those differently from other desktop sites.

+    view_flags |= InputRouter::MOBILE_VIEWPORT;
+
+  return view_flags;

[Xianzhu, 2014/01/14 21:54:19]

Will the individual bits of view_flags be meaningful to InputRouter or be used
for purpose other than touch_ack_timeout?

Raised the question when I was seeking other conditions to opt out the timeout,
which would need new bits, or just InputRouter::DisableTouchAckTimeout().

[jdduke (slow), 2014/01/14 21:56:38]

Currently, no, it's only useful for the ack timeout.  However, 
the flag additions were somewhat speculative... I've had thoughts of filtering
out pinch update events if the page scale is fixed, or event scroll updates if
we know there is no affordance in the scroll offset. 

+}
+
 // Implements the RenderWidgetHostIterator interface. It keeps a list of
 // RenderWidgetHosts, and makes sure it returns a live RenderWidgetHost at each
 // iteration (or NULL if there isn't any left).
 class RenderWidgetHostIteratorImpl : public RenderWidgetHostIterator {
  public:
   RenderWidgetHostIteratorImpl()
       : current_index_(0) {
   }
 
   virtual ~RenderWidgetHostIteratorImpl() {
@@ skipping 1378 matching lines @@
 
 bool RenderWidgetHostImpl::OnSwapCompositorFrame(
     const IPC::Message& message) {
   ViewHostMsg_SwapCompositorFrame::Param param;
   if (!ViewHostMsg_SwapCompositorFrame::Read(&message, &param))
     return false;
   scoped_ptr<cc::CompositorFrame> frame(new cc::CompositorFrame);
   uint32 output_surface_id = param.a;
   param.b.AssignTo(frame.get());
 
-  bool fixed_page_scale =
-      frame->metadata.min_page_scale_factor ==
-          frame->metadata.max_page_scale_factor;
-  int updated_view_flags = fixed_page_scale ? InputRouter::FIXED_PAGE_SCALE
-                                            : InputRouter::VIEW_FLAGS_NONE;
-  input_router_->OnViewUpdated(updated_view_flags);
+  input_router_->OnViewUpdated(
+      GetInputRouterViewFlagsFromCompositorFrameMetadata(frame->metadata));
 
   if (view_) {
     view_->OnSwapCompositorFrame(output_surface_id, frame.Pass());
     view_->DidReceiveRendererFrame();
   } else {
     cc::CompositorFrameAck ack;
     if (frame->gl_frame_data) {
       ack.gl_frame_data = frame->gl_frame_data.Pass();
       ack.gl_frame_data->sync_point = 0;
     } else if (frame->delegated_frame_data) {
@@ skipping 950 matching lines @@
         continue;
       }
       RenderWidgetHostImpl* rwhi = RenderWidgetHostImpl::From(rwh);
       if (rwhi_set.insert(rwhi).second)
         rwhi->FrameSwapped(latency_info);
     }
   }
 }
 
 }  // namespace content