Introduce bottom controls to CC and let it respond to scrolling

cc/ipc/struct_traits_unittest.cc

Index: cc/ipc/struct_traits_unittest.cc
diff --git a/cc/ipc/struct_traits_unittest.cc b/cc/ipc/struct_traits_unittest.cc
index 248ea4c2d5bb7e3a5461d5b8c3a1302cbb0838c2..c83bbbf5a075f00af3cc424809aa2ef77cf01082 100644
--- a/cc/ipc/struct_traits_unittest.cc
+++ b/cc/ipc/struct_traits_unittest.cc
@@ -267,8 +267,10 @@ TEST_F(StructTraitsTest, CompositorFrameMetadata) {
   const float max_page_scale_factor = 4.6f;
   const bool root_overflow_x_hidden = true;
   const bool root_overflow_y_hidden = true;
-  const gfx::Vector2dF location_bar_offset(1234.5f, 5432.1f);
-  const gfx::Vector2dF location_bar_content_translation(1234.5f, 5432.1f);
+  const gfx::Vector2dF top_bar_height(1234.5f, 5432.1f);
+  const float top_bar_shown_ratio(1234.5f, 5432.1f);
+  const gfx::Vector2dF bottom_bar_height(1234.5f, 5432.1f);
+  const float bottom_bar_shown_ratio(1234.5f, 5432.1f);
   const uint32_t root_background_color = 1337;
   Selection<gfx::SelectionBound> selection;
   selection.start.SetEdge(gfx::PointF(1234.5f, 67891.f),
@@ -300,8 +302,10 @@ TEST_F(StructTraitsTest, CompositorFrameMetadata) {
   input.max_page_scale_factor = max_page_scale_factor;
   input.root_overflow_x_hidden = root_overflow_x_hidden;
   input.root_overflow_y_hidden = root_overflow_y_hidden;
-  input.location_bar_offset = location_bar_offset;
-  input.location_bar_content_translation = location_bar_content_translation;
+  input.top_controls_height = top_bar_height;
+  input.top_controls_shown_ratio = top_bar_shown_ratio;
+  input.bottom_controls_height = bottom_bar_height;
+  input.bottom_controls_shown_ratio = bottom_bar_shown_ratio;
   input.root_background_color = root_background_color;
   input.selection = selection;
   input.latency_info = latency_infos;
@@ -320,9 +324,10 @@ TEST_F(StructTraitsTest, CompositorFrameMetadata) {
   EXPECT_EQ(max_page_scale_factor, output.max_page_scale_factor);
   EXPECT_EQ(root_overflow_x_hidden, output.root_overflow_x_hidden);
   EXPECT_EQ(root_overflow_y_hidden, output.root_overflow_y_hidden);
-  EXPECT_EQ(location_bar_offset, output.location_bar_offset);
-  EXPECT_EQ(location_bar_content_translation,
-            output.location_bar_content_translation);
+  EXPECT_EQ(top_bar_height, output.top_controls_height);
+  EXPECT_EQ(top_bar_shown_ratio, output.top_controls_shown_ratio);
+  EXPECT_EQ(bottom_bar_height, output.bottom_controls_height);
+  EXPECT_EQ(bottom_bar_shown_ratio, output.bottom_controls_shown_ratio);
   EXPECT_EQ(root_background_color, output.root_background_color);
   EXPECT_EQ(selection, output.selection);
   EXPECT_EQ(latency_infos.size(), output.latency_info.size());