Improve Recent Apps scrolling performance

- 20fps improvement using software rendering
- 10fps improvement using hardware rendering
- in sw mode, rendering recents background in the recent items themselves and using a bitmap cache to draw individual items (gives perf gains for sw mode)
- in sw and hw mode, no longer doing a fade on the recents scroll view (gives perf gains for hw mode) - instead we draw a black gradient where we would normally fade
- fading recents & notifications immediately when swiped
- removing unused code

Change-Id: I908e2a25b89c9dfbf9b8c8f3810fa43064261b33

2 files changed, 74 insertions, 69 deletions

diff --git a/packages/SystemUI/res/layout-port/status_bar_recent_item.xml b/packages/SystemUI/res/layout-port/status_bar_recent_item.xml
index c0fce71..f6b72d4 100644
--- a/packages/SystemUI/res/layout-port/status_bar_recent_item.xml
+++ b/packages/SystemUI/res/layout-port/status_bar_recent_item.xml
@@ -19,79 +19,84 @@
 -->
 
 <!--    android:background="@drawable/status_bar_closed_default_background" -->
-<RelativeLayout
+<FrameLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_height="wrap_content"
-    android:layout_width="@dimen/status_bar_recents_thumbnail_view_width">
+    android:layout_width="match_parent">
 
-    <FrameLayout android:id="@+id/app_thumbnail"
-        android:layout_width="wrap_content"
+    <RelativeLayout android:id="@+id/recent_item"
         android:layout_height="wrap_content"
-        android:layout_alignParentLeft="true"
-        android:layout_alignParentTop="true"
-        android:clickable="true"
-        android:layout_marginLeft="@dimen/status_bar_recents_thumbnail_left_margin"
-        android:scaleType="center"
-        android:background="@drawable/recents_thumbnail_bg"
-        android:foreground="@drawable/recents_thumbnail_overlay">
-        <ImageView android:id="@+id/app_thumbnail_image"
-            android:layout_width="match_parent"
-            android:layout_height="match_parent"
-            android:visibility="invisible"
-        />
-    </FrameLayout>
+        android:layout_width="match_parent">
 
-    <ImageView android:id="@+id/app_icon"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:layout_alignLeft="@id/app_thumbnail"
-        android:layout_alignTop="@id/app_thumbnail"
-        android:layout_marginLeft="@dimen/status_bar_recents_app_icon_left_margin"
-        android:layout_marginTop="@dimen/status_bar_recents_app_icon_top_margin"
-        android:maxWidth="@dimen/status_bar_recents_thumbnail_max_width"
-        android:maxHeight="@dimen/status_bar_recents_thumbnail_max_height"
-        android:adjustViewBounds="true"
-    />
+        <FrameLayout android:id="@+id/app_thumbnail"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_alignParentLeft="true"
+            android:layout_alignParentTop="true"
+            android:clickable="true"
+            android:layout_marginLeft="@dimen/status_bar_recents_thumbnail_left_margin"
+            android:scaleType="center"
+            android:background="@drawable/recents_thumbnail_bg"
+            android:foreground="@drawable/recents_thumbnail_overlay">
+            <ImageView android:id="@+id/app_thumbnail_image"
+                android:layout_width="match_parent"
+                android:layout_height="match_parent"
+                android:visibility="invisible"
+            />
+        </FrameLayout>
 
-    <TextView android:id="@+id/app_label"
-        android:layout_width="@dimen/status_bar_recents_app_label_width"
-        android:layout_height="wrap_content"
-        android:textSize="@dimen/status_bar_recents_app_label_text_size"
-        android:fadingEdge="horizontal"
-        android:fadingEdgeLength="@dimen/status_bar_recents_fading_edge_length"
-        android:scrollHorizontally="true"
-        android:layout_alignParentLeft="true"
-        android:layout_alignTop="@id/app_icon"
-        android:layout_marginLeft="@dimen/status_bar_recents_app_label_left_margin"
-        android:singleLine="true"
-        android:ellipsize="marquee"
-    />
+        <ImageView android:id="@+id/app_icon"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_alignLeft="@id/app_thumbnail"
+            android:layout_alignTop="@id/app_thumbnail"
+            android:layout_marginLeft="@dimen/status_bar_recents_app_icon_left_margin"
+            android:layout_marginTop="@dimen/status_bar_recents_app_icon_top_margin"
+            android:maxWidth="@dimen/status_bar_recents_thumbnail_max_width"
+            android:maxHeight="@dimen/status_bar_recents_thumbnail_max_height"
+            android:adjustViewBounds="true"
+        />
 
-    <View android:id="@+id/recents_callout_line"
-        android:layout_width="@dimen/status_bar_recents_app_label_width"
-        android:layout_height="1dip"
-        android:layout_alignParentLeft="true"
-        android:layout_marginLeft="@dimen/status_bar_recents_app_label_left_margin"
-        android:layout_toLeftOf="@id/app_thumbnail"
-        android:layout_below="@id/app_label"
-        android:layout_marginRight="3dip"
-        android:layout_marginTop="3dip"
-        android:background="@drawable/recents_callout_line"
-    />
+        <TextView android:id="@+id/app_label"
+            android:layout_width="@dimen/status_bar_recents_app_label_width"
+            android:layout_height="wrap_content"
+            android:textSize="@dimen/status_bar_recents_app_label_text_size"
+            android:fadingEdge="horizontal"
+            android:fadingEdgeLength="@dimen/status_bar_recents_fading_edge_length"
+            android:scrollHorizontally="true"
+            android:layout_alignParentLeft="true"
+            android:layout_alignTop="@id/app_icon"
+            android:layout_marginLeft="@dimen/status_bar_recents_app_label_left_margin"
+            android:singleLine="true"
+            android:ellipsize="marquee"
+        />
 
-    <TextView android:id="@+id/app_description"
-        android:layout_width="@dimen/status_bar_recents_app_label_width"
-        android:layout_height="wrap_content"
-        android:textSize="@dimen/status_bar_recents_app_description_text_size"
-        android:fadingEdge="horizontal"
-        android:fadingEdgeLength="@dimen/status_bar_recents_fading_edge_length"
-        android:scrollHorizontally="true"
-        android:layout_alignParentLeft="true"
-        android:layout_marginLeft="@dimen/status_bar_recents_app_label_left_margin"
-        android:layout_below="@id/recents_callout_line"
-        android:layout_marginTop="3dip"
-        android:singleLine="true"
-        android:ellipsize="marquee"
-    />
+        <View android:id="@+id/recents_callout_line"
+            android:layout_width="@dimen/status_bar_recents_app_label_width"
+            android:layout_height="1dip"
+            android:layout_alignParentLeft="true"
+            android:layout_marginLeft="@dimen/status_bar_recents_app_label_left_margin"
+            android:layout_toLeftOf="@id/app_thumbnail"
+            android:layout_below="@id/app_label"
+            android:layout_marginRight="3dip"
+            android:layout_marginTop="3dip"
+            android:background="@drawable/recents_callout_line"
+        />
+
+        <TextView android:id="@+id/app_description"
+            android:layout_width="@dimen/status_bar_recents_app_label_width"
+            android:layout_height="wrap_content"
+            android:textSize="@dimen/status_bar_recents_app_description_text_size"
+            android:fadingEdge="horizontal"
+            android:fadingEdgeLength="@dimen/status_bar_recents_fading_edge_length"
+            android:scrollHorizontally="true"
+            android:layout_alignParentLeft="true"
+            android:layout_marginLeft="@dimen/status_bar_recents_app_label_left_margin"
+            android:layout_below="@id/recents_callout_line"
+            android:layout_marginTop="3dip"
+            android:singleLine="true"
+            android:ellipsize="marquee"
+        />
 
-</RelativeLayout>
+    </RelativeLayout>
+</FrameLayout>
diff --git a/packages/SystemUI/res/layout-port/status_bar_recent_panel.xml b/packages/SystemUI/res/layout-port/status_bar_recent_panel.xml
index c680b8e..dd25cf9 100644
--- a/packages/SystemUI/res/layout-port/status_bar_recent_panel.xml
+++ b/packages/SystemUI/res/layout-port/status_bar_recent_panel.xml
@@ -40,7 +40,7 @@
             android:layout_marginTop="@*android:dimen/status_bar_height">
             <com.android.systemui.recent.RecentsVerticalScrollView
                 android:id="@+id/recents_container"
-                android:layout_width="@dimen/status_bar_recents_width"
+                android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_marginRight="0dp"
                 android:divider="@null"
@@ -53,7 +53,7 @@
                 android:clipChildren="false">
 
                 <LinearLayout android:id="@+id/recents_linear_layout"
-                    android:layout_width="wrap_content"
+                    android:layout_width="match_parent"
                     android:layout_height="wrap_content"
                     android:orientation="vertical"
                     android:clipToPadding="false"