Introduce bottom controls to CC and let it respond to scrolling

ui/android/delegated_frame_host_android.cc

 // Copyright 2016 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 "ui/android/delegated_frame_host_android.h"
 
 #include "base/logging.h"
 #include "cc/layers/solid_color_layer.h"
 #include "cc/layers/surface_layer.h"
 #include "cc/output/compositor_frame.h"
@@ skipping 95 matching lines @@
   if (!surface_factory_) {
     surface_factory_ =
         base::WrapUnique(new cc::SurfaceFactory(surface_manager_, this));
   }
 
   cc::RenderPass* root_pass =
       frame.delegated_frame_data->render_pass_list.back().get();
   gfx::Size surface_size = root_pass->output_rect.size();
 
   if (!current_frame_ || surface_size != current_frame_->surface_size ||
-      current_frame_->location_bar_content_translation !=
-          frame.metadata.location_bar_content_translation ||
+      current_frame_->top_controls_shown_ratio !=
+          frame.metadata.top_controls_shown_ratio ||

[Khushal, 2016/08/17 04:45:34]

Should this check for a change in height too?

+      current_frame_->bottom_controls_shown_ratio !=
+          frame.metadata.bottom_controls_shown_ratio ||
       current_frame_->viewport_selection != frame.metadata.selection) {
     DestroyDelegatedContent();
     DCHECK(!content_layer_);
     DCHECK(!current_frame_);
 
     current_frame_ = base::MakeUnique<FrameData>();
     current_frame_->surface_id = surface_id_allocator_->GenerateId();
     surface_factory_->Create(current_frame_->surface_id);
 
     current_frame_->surface_size = surface_size;
-    current_frame_->location_bar_content_translation =
-        frame.metadata.location_bar_content_translation;
+    current_frame_->top_controls_shown_ratio =

[Khushal, 2016/08/17 04:45:34]

Need to update the top and bottom height also here.

+        frame.metadata.top_controls_shown_ratio;
+    current_frame_->bottom_controls_shown_ratio =
+            frame.metadata.bottom_controls_shown_ratio;
     current_frame_->viewport_selection = frame.metadata.selection;
     content_layer_ =
         CreateSurfaceLayer(surface_manager_, current_frame_->surface_id,
                            current_frame_->surface_size);
     view_->GetLayer()->AddChild(content_layer_);
     UpdateBackgroundLayer();
   }
 
   surface_factory_->SubmitCompositorFrame(current_frame_->surface_id,
                                           std::move(frame), draw_callback);
@@ skipping 82 matching lines @@
   // The background layer draws in 2 cases:
   // 1) When we don't have any content from the renderer.
   // 2) When the bounds of the content received from the renderer does not match
   // the desired content bounds.
   bool background_is_drawable = false;
 
   if (current_frame_) {
     float device_scale_factor = gfx::DeviceDisplayInfo().GetDIPScale();
     gfx::Size content_size_in_dip = gfx::ConvertSizeToDIP(
         device_scale_factor, current_frame_->surface_size);
+    float top_bar_shown = current_frame_->top_controls_height *
+                          current_frame_->top_controls_shown_ratio;
+    float bottom_bar_shown = current_frame_->bottom_controls_height *
+                             current_frame_->bottom_controls_shown_ratio;
     content_size_in_dip.set_height(
-        content_size_in_dip.height() +
-        current_frame_->location_bar_content_translation.y());
+        content_size_in_dip.height() - top_bar_shown - bottom_bar_shown);

[Khushal, 2016/08/17 04:45:34]

The top and bottom bar should be added. This will give us the total viewport
size for this render frame, and we decide to show the background based on
whether the container size matches this.

     background_is_drawable =
         content_size_in_dip.width() < container_size_in_dip_.width() ||
         content_size_in_dip.height() < container_size_in_dip_.height();
   } else {
     background_is_drawable = true;
   }
 
   background_layer_->SetIsDrawable(background_is_drawable);
 }
 
 }  // namespace ui