[Payments] Add UI elements to secure branding for payments

chrome/android/java/src/org/chromium/chrome/browser/payments/ui/PaymentRequestBottomBar.java

+// Copyright 2017 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.payments.ui;
+
+import android.content.Context;
+import android.util.AttributeSet;
+import android.view.View;
+import android.view.View.MeasureSpec;
+import android.widget.LinearLayout;
+
+import org.chromium.chrome.R;
+
+/** This class represents a bar to display at the bottom of the payment request UI. */
+public class PaymentRequestBottomBar extends LinearLayout {
+    public PaymentRequestBottomBar(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    @Override
+    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+        // Views layout_width must be set to match_parent.
+        assert MeasureSpec.getMode(widthMeasureSpec) == MeasureSpec.EXACTLY;
+
+        View logoWithName = findViewById(R.id.logo_name);

[gone, 2017/02/17 23:17:10]

Cache the views in onFinishInflate() so you're not searching every single time
the group is measured.

[gogerald1, 2017/02/20 15:18:36]

Done.

+        measureChild(logoWithName, widthMeasureSpec, heightMeasureSpec);
+        int logoWithNameWidth = logoWithName.getMeasuredWidth();
+
+        View logo = findViewById(R.id.logo);
+        measureChild(logo, widthMeasureSpec, heightMeasureSpec);
+        int logoWidth = logo.getMeasuredWidth();
+
+        View primaryButton = findViewById(R.id.button_primary);
+        measureChild(primaryButton, widthMeasureSpec, heightMeasureSpec);
+        int primaryButtonWidth = primaryButton.getMeasuredWidth();
+
+        View secondaryButton = findViewById(R.id.button_secondary);
+        measureChild(secondaryButton, widthMeasureSpec, heightMeasureSpec);
+        int secondaryButtonWidth = secondaryButton.getMeasuredWidth();
+
+        int blankSpaceWidth = 0;
+        int totolWidth = MeasureSpec.getSize(widthMeasureSpec);

[gone, 2017/02/17 23:17:11]

totalWidth

[gogerald1, 2017/02/20 15:18:36]

Done.

+        int widthWithoutLogo =
+                primaryButtonWidth + secondaryButtonWidth + getPaddingLeft() + getPaddingRight();

[gone, 2017/02/17 23:17:11]

This calculation doesn't account for the margins defined on the LayoutParams. 
Those aren't currently set in your layout, but you should try to properly handle
them.

[gogerald1, 2017/02/20 15:18:36]

Done.

+        if (widthWithoutLogo + logoWithNameWidth <= totolWidth) {
+            logo.setVisibility(View.GONE);
+            logoWithName.setVisibility(View.VISIBLE);
+            blankSpaceWidth = totolWidth - widthWithoutLogo - logoWithNameWidth;
+        } else if (widthWithoutLogo + logoWidth <= totolWidth) {
+            logo.setVisibility(View.VISIBLE);
+            logoWithName.setVisibility(View.GONE);
+            blankSpaceWidth = totolWidth - widthWithoutLogo - logoWidth;
+        } else {
+            logoWithName.setVisibility(View.GONE);
+            logo.setVisibility(View.GONE);
+            blankSpaceWidth = totolWidth - widthWithoutLogo;
+            assert false
+                    : "Screen width is expected to fit the two buttons plus the logo at least.";

[gone, 2017/02/17 23:17:11]

1) Asserting here isn't helpful; the fallback case of just showing the buttons
is as good as you can get.

2) You're not checking if blankSpaceWidth is negative; I'm not sure what
measureChild will do in that case.  You should clamp blankSpaceWidth >= 0.

[gogerald1, 2017/02/20 15:18:36]

Done. Thought negative would be considered as zero.

+        }
+
+        // Sets the space width.
+        View space = findViewById(R.id.space);
+        space.getLayoutParams().width = blankSpaceWidth;
+        measureChild(space, MeasureSpec.makeMeasureSpec(blankSpaceWidth, MeasureSpec.EXACTLY),
+                heightMeasureSpec);
+
+        // Note that logoWithName and logo must have the same height.
+        int measuredHeight = getPaddingTop() + getPaddingBottom()
+                + Math.max(logoWithName.getMeasuredHeight(),

[gone, 2017/02/17 23:17:11]

Pull out the max height calculation.  The indentation makes it painful to read.

[gogerald1, 2017/02/20 15:18:36]

Done.

+                          Math.max(primaryButton.getMeasuredHeight(),
+                                  secondaryButton.getMeasuredHeight()));
+        int measuredHeightSpec = MeasureSpec.makeMeasureSpec(measuredHeight, MeasureSpec.EXACTLY);
+        setMeasuredDimension(widthMeasureSpec, measuredHeightSpec);
+    }
+}