Introduce bottom controls to CC and let it respond to scrolling

ui/android/delegated_frame_host_android.cc

Index: ui/android/delegated_frame_host_android.cc
diff --git a/ui/android/delegated_frame_host_android.cc b/ui/android/delegated_frame_host_android.cc
index 6e786dc9adb2d85cff2a0f62c5c29714d9189906..f2307b6381bdcace813d54c2592a20926061bf83 100644
--- a/ui/android/delegated_frame_host_android.cc
+++ b/ui/android/delegated_frame_host_android.cc
@@ -113,8 +113,10 @@ void DelegatedFrameHostAndroid::SubmitCompositorFrame(
   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_);
@@ -125,8 +127,10 @@ void DelegatedFrameHostAndroid::SubmitCompositorFrame(
     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,
@@ -229,9 +233,12 @@ void DelegatedFrameHostAndroid::UpdateBackgroundLayer() {
     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();