Fix layout transition from Display->Ambient Display to Gestures

1. Add handling in Gestures settings to scroll to the corresponding
preference when launching from Display->Ambient Display
2. Remove the bitmap creation for the video preview image
3. Use a custom aspect ration framee layout to hold the animation
instead to avoid resizing of the animation view.

Bug: 29795707
Change-Id: I67209ba2508a93da4fc46ff20986309dbe5a83d5

src/com/android/settings/widget/AspectRatioFrameLayout.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the
+ * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package com.android.settings.widget;
+
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.util.AttributeSet;
+import android.widget.FrameLayout;
+
+import com.android.settings.R;
+
+/**
+ * A {@link FrameLayout} with customizable aspect ration.
+ * This is used to avoid dynamically calculating the height for the frame. Default aspect
+ * ratio will be 1 if none is set in layout attribute.
+ */
+public final class AspectRatioFrameLayout extends FrameLayout {
+
+    private float mAspectRatio = 1.0f;
+
+    public AspectRatioFrameLayout(Context context) {
+        this(context, null);
+    }
+
+    public AspectRatioFrameLayout(Context context, AttributeSet attrs) {
+        this(context, attrs, 0);
+    }
+
+    public AspectRatioFrameLayout(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+        if (attrs != null) {
+            TypedArray array =
+                    context.obtainStyledAttributes(attrs, R.styleable.AspectRatioFrameLayout);
+            mAspectRatio = array.getFloat(
+                    R.styleable.AspectRatioFrameLayout_aspectRatio, 1.0f);
+            array.recycle();
+        }
+    }
+
+    @Override
+    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+        super.onMeasure(widthMeasureSpec, (int) (widthMeasureSpec / mAspectRatio));
+    }
+
+}