Control display of shadows for multi-window in DecorView

Allows us to display shadows without needing the NonClientDecorView.
For example, windows in pinned stack don't have a NonClientDecorView.

Bug: 25006507
Change-Id: Id573a30942a9bfcd002b86f0956d0b2a14ec2c2b
diff --git a/core/java/com/android/internal/widget/NonClientDecorView.java b/core/java/com/android/internal/widget/NonClientDecorView.java
index 33b8e05..1f01759 100644
--- a/core/java/com/android/internal/widget/NonClientDecorView.java
+++ b/core/java/com/android/internal/widget/NonClientDecorView.java
@@ -28,24 +28,18 @@
 import android.view.ViewOutlineProvider;
 import android.view.Window;
 import android.util.Log;
-import android.util.TypedValue;
 
 import com.android.internal.R;
-import com.android.internal.policy.DecorView;
 import com.android.internal.policy.PhoneWindow;
 
 /**
  * This class represents the special screen elements to control a window on free form
- * environment. All thse screen elements are added in the "non client area" which is the area of
+ * environment. All these screen elements are added in the "non client area" which is the area of
  * the window which is handled by the OS and not the application.
  * As such this class handles the following things:
  * <ul>
  * <li>The caption, containing the system buttons like maximize, close and such as well as
  * allowing the user to drag the window around.</li>
- * <li>The shadow - which is changing dependent on the window focus.</li>
- * <li>The border around the client area (if there is one).</li>
- * <li>The resize handles which allow to resize the window.</li>
- * </ul>
  * After creating the view, the function
  * {@link #setPhoneWindow} needs to be called to make
  * the connection to it's owning PhoneWindow.
@@ -62,12 +56,7 @@
 public class NonClientDecorView extends LinearLayout
         implements View.OnClickListener, View.OnTouchListener {
     private final static String TAG = "NonClientDecorView";
-    // The height of a window which has focus in DIP.
-    private final int DECOR_SHADOW_FOCUSED_HEIGHT_IN_DIP = 20;
-    // The height of a window which has not in DIP.
-    private final int DECOR_SHADOW_UNFOCUSED_HEIGHT_IN_DIP = 5;
     private PhoneWindow mOwner = null;
-    private boolean mWindowHasShadow = false;
     private boolean mShowDecor = false;
 
     // True if the window is being dragged.
@@ -76,17 +65,6 @@
     // True when the left mouse button got released while dragging.
     private boolean mLeftMouseButtonReleased;
 
-    // True if this window is resizable (which is currently only true when the decor is shown).
-    public boolean mVisible = false;
-
-    // The current focus state of the window for updating the window elevation.
-    private boolean mWindowHasFocus = true;
-
-    // Cludge to address b/22668382: Set the shadow size to the maximum so that the layer
-    // size calculation takes the shadow size into account. We set the elevation currently
-    // to max until the first layout command has been executed.
-    private boolean mAllowUpdateElevation = false;
-
     public NonClientDecorView(Context context) {
         super(context);
     }
@@ -99,14 +77,10 @@
         super(context, attrs, defStyle);
     }
 
-    public void setPhoneWindow(PhoneWindow owner, boolean showDecor, boolean windowHasShadow) {
+    public void setPhoneWindow(PhoneWindow owner, boolean showDecor) {
         mOwner = owner;
-        mWindowHasShadow = windowHasShadow;
         mShowDecor = showDecor;
         updateCaptionVisibility();
-        if (mWindowHasShadow) {
-            initializeElevation();
-        }
         // By changing the outline provider to BOUNDS, the window can remove its
         // background without removing the shadow.
         mOwner.getDecorView().setOutlineProvider(ViewOutlineProvider.BOUNDS);
@@ -164,15 +138,10 @@
     /**
      * The phone window configuration has changed and the decor needs to be updated.
      * @param showDecor True if the decor should be shown.
-     * @param windowHasShadow True when the window should show a shadow.
-     **/
-    public void onConfigurationChanged(boolean showDecor, boolean windowHasShadow) {
+     */
+    public void onConfigurationChanged(boolean showDecor) {
         mShowDecor = showDecor;
         updateCaptionVisibility();
-        if (windowHasShadow != mWindowHasShadow) {
-            mWindowHasShadow = windowHasShadow;
-            initializeElevation();
-        }
     }
 
     @Override
@@ -185,23 +154,6 @@
     }
 
     @Override
-    public void onWindowFocusChanged(boolean hasWindowFocus) {
-        mWindowHasFocus = hasWindowFocus;
-        updateElevation();
-        super.onWindowFocusChanged(hasWindowFocus);
-    }
-
-    @Override
-    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
-        // If the application changed its SystemUI metrics, we might also have to adapt
-        // our shadow elevation.
-        updateElevation();
-        mAllowUpdateElevation = true;
-
-        super.onLayout(changed, left, top, right, bottom);
-    }
-
-    @Override
     public void addView(View child, int index, ViewGroup.LayoutParams params) {
         // Make sure that we never get more then one client area in our view.
         if (index >= 2 || getChildCount() >= 2) {
@@ -229,60 +181,6 @@
         View caption = getChildAt(0);
         caption.setVisibility(invisible ? GONE : VISIBLE);
         caption.setOnTouchListener(this);
-        mVisible = !invisible;
-    }
-
-    /**
-     * The elevation gets set for the first time and the framework needs to be informed that
-     * the surface layer gets created with the shadow size in mind.
-     **/
-    private void initializeElevation() {
-        // TODO(skuhne): Call setMaxElevation here accordingly after b/22668382 got fixed.
-        mAllowUpdateElevation = false;
-        if (mWindowHasShadow) {
-            updateElevation();
-        } else {
-            mOwner.setElevation(0);
-        }
-    }
-
-    /**
-     * The shadow height gets controlled by the focus to visualize highlighted windows.
-     * Note: This will overwrite application elevation properties.
-     * Note: Windows which have (temporarily) changed their attributes to cover the SystemUI
-     *       will get no shadow as they are expected to be "full screen".
-     **/
-    public void updateElevation() {
-        float elevation = 0;
-        // Do not use a shadow when we are in resizing mode (mRenderer not null) since the shadow
-        // is bound to the content size and not the target size.
-        if (mWindowHasShadow
-                && ((DecorView) mOwner.getDecorView()).mBackdropFrameRenderer == null) {
-            boolean fill = isFillingScreen();
-            elevation = fill ? 0 :
-                    (mWindowHasFocus ? DECOR_SHADOW_FOCUSED_HEIGHT_IN_DIP :
-                            DECOR_SHADOW_UNFOCUSED_HEIGHT_IN_DIP);
-            // TODO(skuhne): Remove this if clause once b/22668382 got fixed.
-            if (!mAllowUpdateElevation && !fill) {
-                elevation = DECOR_SHADOW_FOCUSED_HEIGHT_IN_DIP;
-            }
-            // Convert the DP elevation into physical pixels.
-            elevation = dipToPx(elevation);
-        }
-        // Don't change the elevation if it didn't change since it can require some time.
-        if (mOwner.getDecorView().getElevation() != elevation) {
-            mOwner.setElevation(elevation);
-        }
-    }
-
-    /**
-     * Converts a DIP measure into physical pixels.
-     * @param dip The dip value.
-     * @return Returns the number of pixels.
-     */
-    private float dipToPx(float dip) {
-        return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dip,
-                getResources().getDisplayMetrics());
     }
 
     /**