Address NewApi and other Android lint warnings in src/chrome.

chrome/android/java/src/org/chromium/chrome/browser/widget/ButtonCompat.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.widget;
 
 import android.animation.AnimatorInflater;
 import android.annotation.TargetApi;
 import android.content.Context;
 import android.content.res.ColorStateList;
@@ skipping 20 matching lines @@
  *
  *   <org.chromium.chrome.browser.widget.ButtonCompat
  *       android:layout_width="wrap_content"
  *       android:layout_height="wrap_content"
  *       android:text="Click me"
  *       chrome:buttonColor="#f00" />
  *
  * Note: To ensure the button's shadow is fully visible, you may need to set
  * android:clipToPadding="false" on the button's parent view.
  */
+@TargetApi(Build.VERSION_CODES.LOLLIPOP)
 public class ButtonCompat extends Button {
 
     private static final float PRE_L_PRESSED_BRIGHTNESS = 0.85f;
     private static final int DISABLED_COLOR = 0x1F000000;
 
     private int mColor;
 
     /**
      * Returns a new borderless material-style button.
      */
@@ skipping 92 matching lines @@
         return DISABLED_COLOR;
     }
 
     private static int getColorFromAttributeSet(Context context, AttributeSet attrs) {
         TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ButtonCompat, 0, 0);
         int color = a.getColor(R.styleable.ButtonCompat_buttonColor, Color.WHITE);
         a.recycle();
         return color;
     }
 }