Make tile size a function of the device scale factor.

cc/trees/layer_tree_host_impl.cc

 // Copyright 2011 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 "cc/trees/layer_tree_host_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 71 matching lines @@
 #include "cc/trees/latency_info_swap_promise_monitor.h"
 #include "cc/trees/layer_tree_host.h"
 #include "cc/trees/layer_tree_host_common.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "cc/trees/single_thread_proxy.h"
 #include "cc/trees/tree_synchronizer.h"
 #include "gpu/GLES2/gl2extchromium.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
 #include "ui/gfx/geometry/point_conversions.h"
 #include "ui/gfx/geometry/rect_conversions.h"
+#include "ui/gfx/geometry/safe_integer_conversions.h"
 #include "ui/gfx/geometry/scroll_offset.h"
 #include "ui/gfx/geometry/size_conversions.h"
 #include "ui/gfx/geometry/vector2d_conversions.h"
 
 namespace cc {
 namespace {
 
 // Small helper class that saves the current viewport location as the user sees
 // it and resets to the same location.
 class ViewportAnchor {
@@ skipping 2299 matching lines @@
     active_tree_->SetViewportSizeInvalid();
 
   device_viewport_size_ = device_viewport_size;
 
   UpdateViewportContainerSizes();
   client_->OnCanDrawStateChanged(CanDraw());
   SetFullRootLayerDamage();
   active_tree_->set_needs_update_draw_properties();
 }
 
-const gfx::Rect LayerTreeHostImpl::ViewportRectForTilePriority() const {
+gfx::Rect LayerTreeHostImpl::ViewportRectForTilePriority() const {
   if (viewport_rect_for_tile_priority_.IsEmpty())
     return DeviceViewport();
 
   return viewport_rect_for_tile_priority_;
 }
 
 gfx::Size LayerTreeHostImpl::DrawViewportSize() const {
+  // XXX DIE DIE DIE DIE

[enne (OOO), 2016/06/28 18:39:02]

https://www.youtube.com/watch?v=UrHVBfSaPtA

   return DeviceViewport().size();
 }
 
+gfx::Size LayerTreeHostImpl::GetStableScreenSize(

[enne (OOO), 2016/06/28 18:39:01]

How does this relate to gfx::DeviceDisplayInfo::GetPhysicalDisplay*? Is it the
same, always?

+    const LayerTreeImpl* tree) const {
+  // TODO(crbug.com/622885): Get a stable screen size for any platform from
+  // the embedder.
+
+  // This size does not include an external viewport size.
+  int width = device_viewport_size_.width();
+  int height = device_viewport_size_.height();
+  if (tree->top_controls_shrink_blink_size())
+    height += gfx::ToCeiledInt(tree->top_controls_height() *
+                               tree->device_scale_factor());
+
+  if (external_viewport_.IsEmpty())
+    return gfx::Size(width, height);
+
+  int external_width = external_viewport_.width();
+  int external_height = external_viewport_.height();
+  if (tree->top_controls_shrink_blink_size())
+    external_height += gfx::ToCeiledInt(tree->top_controls_height() *
+                                        tree->device_scale_factor());
+
+  // Take the smaller of the two. An external viewport may be much larger than
+  // what will actually be on screen, or much smaller.
+  return gfx::Size(std::min(width, external_width),
+                   std::min(height, external_height));
+}
+
 gfx::Rect LayerTreeHostImpl::DeviceViewport() const {
   if (external_viewport_.IsEmpty())
     return gfx::Rect(device_viewport_size_);
 
   return external_viewport_;
 }
 
 gfx::Rect LayerTreeHostImpl::DeviceClip() const {
   if (external_clip_.IsEmpty())
     return DeviceViewport();
@@ skipping 1578 matching lines @@
   return task_runner_provider_->HasImplThread();
 }
 
 bool LayerTreeHostImpl::CommitToActiveTree() const {
   // In single threaded mode we skip the pending tree and commit directly to the
   // active tree.
   return !task_runner_provider_->HasImplThread();
 }
 
 }  // namespace cc