[Unity][Android] Add first part of SigninView

This CL adds SigninView to SigninFragmentBase and introduces the first
chunk of SigninView layout: SigninScrollView and a bottom button bar.
SigninScrollView implements observable ScrollView similarly to
AccountSigninConfirmationView, but without special onMeasure. Buttons
doesn't have android:text specified as SigninFragmentBase will set texts
for UI elements programmatically (similarly to
AccountSigninView.updateConsentText).
The rest of this layout will be added by subsequent CLs.

Bug: 814728
Change-Id: I3ac2c5fbdb41101a768abc70b3d1c3daa85fccb1
Reviewed-on: https://chromium-review.googlesource.com/962792Reviewed-by: Bernhard Bauer <bauerb@chromium.org>
Commit-Queue: Boris Sazonov <bsazonov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543426}

chrome/android/java/res/layout/signin_view.xml

+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2018 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. -->
+<org.chromium.chrome.browser.signin.SigninView
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:chrome="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+    <org.chromium.chrome.browser.signin.SigninScrollView
+        android:id="@+id/signin_scroll_view"
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:fadingEdgeLength="48dp"
+        android:layout_weight="1"
+        android:requiresFadingEdge="vertical"
+        android:scrollbars="none">
+        <!-- TODO(https://crbug.com/819142): Add the rest of the layout. -->
+    </org.chromium.chrome.browser.signin.SigninScrollView>
+    <LinearLayout
+        android:id="@+id/button_bar"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal"
+        android:padding="16dp">
+        <!-- TODO(https://crbug.com/819142): Use textAppearance instead of text* attributes. -->
+        <Button
+            android:id="@+id/negative_button"
+            style="@style/ButtonCompatBorderless"
+            android:layout_width="wrap_content"
+            android:layout_height="36dp"
+            android:paddingEnd="@dimen/fre_button_padding"
+            android:paddingStart="@dimen/fre_button_padding"
+            android:textAllCaps="true"
+            android:textColor="@color/light_active_color"
+            android:textSize="14sp"
+            tools:text="@string/no_thanks"/>
+        <View
+            android:layout_width="0dp"
+            android:layout_height="0dp"
+            android:layout_weight="1"
+            android:visibility="invisible"/>
+        <!-- TODO(https://crbug.com/819142): Specify WhiteBody as textAppearance. -->
+        <org.chromium.ui.widget.ButtonCompat
+            android:id="@+id/positive_button"
+            style="@style/WhiteBody"
+            android:layout_width="wrap_content"
+            android:layout_height="36dp"
+            android:paddingEnd="@dimen/fre_button_padding"
+            android:paddingStart="@dimen/fre_button_padding"
+            android:textAllCaps="true"
+            chrome:buttonColor="@color/light_active_color"
+            chrome:buttonRaised="false"
+            tools:text="@string/signin_accept_button"/>
+        <!-- TODO(https://crbug.com/819142): Use textAppearance instead of text* attributes. -->
+        <Button
+            android:id="@+id/more_button"
+            style="@style/ButtonCompatBorderless"
+            android:layout_width="wrap_content"
+            android:layout_height="36dp"
+            android:drawableEnd="@drawable/down_arrow"
+            android:drawablePadding="8dp"
+            android:textAllCaps="true"
+            android:textColor="@color/light_active_color"
+            android:textSize="@dimen/text_size_medium"
+            android:visibility="gone"
+            tools:text="@string/more"/>
+        <View
+            android:id="@+id/positive_button_end_padding"
+            android:layout_width="0dp"
+            android:layout_height="0dp"
+            android:layout_weight="1"
+            android:visibility="gone"/>
+    </LinearLayout>
+</org.chromium.chrome.browser.signin.SigninView>

chrome/android/java/src/org/chromium/chrome/browser/signin/SigninFragmentBase.java

@@ -8,7 +8,11 @@ import android.app.Fragment;
 import android.os.Bundle;
 import android.support.annotation.Nullable;
 import android.support.annotation.StringRes;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
 
+import org.chromium.base.metrics.RecordUserAction;
 import org.chromium.chrome.R;
 
 /**
@@ -22,6 +26,8 @@ public abstract class SigninFragmentBase extends Fragment {
     private static final String ARGUMENT_ACCESS_POINT = "SigninFragmentBase.AccessPoint";
 
     private @SigninAccessPoint int mSigninAccessPoint;
+
+    private SigninView mView;
     private @StringRes int mCancelButtonTextId = R.string.cancel;
 
     /**
@@ -81,4 +87,38 @@ public abstract class SigninFragmentBase extends Fragment {
             mCancelButtonTextId = R.string.no_thanks;
         }
     }
+
+    @Override
+    public View onCreateView(
+            LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
+        mView = (SigninView) inflater.inflate(R.layout.signin_view, container, false);
+        mView.getAcceptButton().setVisibility(View.GONE);
+        mView.getMoreButton().setVisibility(View.VISIBLE);
+        mView.getMoreButton().setOnClickListener(view -> {
+            mView.getScrollView().smoothScrollBy(0, mView.getScrollView().getHeight());
+            // TODO(https://crbug.com/821127): Revise this user action.
+            RecordUserAction.record("Signin_MoreButton_Shown");
+        });
+        mView.getScrollView().setScrolledToBottomObserver(this::showAcceptButton);
+
+        mView.getRefuseButton().setOnClickListener(view -> {
+            setButtonsEnabled(false);
+            onSigninRefused();
+        });
+
+        // TODO(https://crbug.com/814728): Set texts for UI elements
+
+        return mView;
+    }
+
+    private void showAcceptButton() {
+        mView.getAcceptButton().setVisibility(View.VISIBLE);
+        mView.getMoreButton().setVisibility(View.GONE);
+        mView.getScrollView().setScrolledToBottomObserver(null);
+    }
+
+    private void setButtonsEnabled(boolean enabled) {
+        mView.getAcceptButton().setEnabled(enabled);
+        mView.getRefuseButton().setEnabled(enabled);
+    }
 }

chrome/android/java/src/org/chromium/chrome/browser/signin/SigninScrollView.java

+// Copyright 2018 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.signin;
+
+import android.content.Context;
+import android.support.annotation.Nullable;
+import android.util.AttributeSet;
+import android.view.ViewTreeObserver;
+import android.widget.ScrollView;
+
+/**
+ * ScrollView without the top edge that also sends notification when it is scrolled to the bottom.
+ */
+public class SigninScrollView extends ScrollView {
+    private final ViewTreeObserver.OnGlobalLayoutListener mOnGlobalLayoutListener =
+            this::checkScrolledToBottom;
+    private final ViewTreeObserver.OnScrollChangedListener mOnScrollChangedListener =
+            this::checkScrolledToBottom;
+    private @Nullable Runnable mObserver;
+
+    public SigninScrollView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    @Override
+    protected float getTopFadingEdgeStrength() {
+        // Disable fading out effect at the top of this ScrollView.
+        return 0;
+    }
+
+    @Override
+    protected void onDetachedFromWindow() {
+        removeObserver();
+        super.onDetachedFromWindow();
+    }
+
+    private void checkScrolledToBottom() {
+        if (mObserver == null) return;
+        if (getChildCount() == 0) {
+            // The ScrollView is definitely scrolled to bottom if there are no children.
+            mObserver.run();
+            return;
+        }
+        if ((getHeight() + getScrollY()) < getChildAt(getChildCount() - 1).getBottom()) return;
+        mObserver.run();
+    }
+
+    /**
+     * Sets observer. Regardless of the passed value, notifications for the previous observer will
+     * be canceled.
+     * @param observer The Runnable to receive notification when SigninScrollView is scrolled to
+     *         bottom, or null to clear the observer.
+     */
+    public void setScrolledToBottomObserver(@Nullable Runnable observer) {
+        removeObserver();
+        if (observer == null) return;
+        mObserver = observer;
+        getViewTreeObserver().addOnGlobalLayoutListener(mOnGlobalLayoutListener);
+        getViewTreeObserver().addOnScrollChangedListener(mOnScrollChangedListener);
+    }
+
+    private void removeObserver() {
+        if (mObserver == null) return;
+        mObserver = null;
+        getViewTreeObserver().removeOnGlobalLayoutListener(mOnGlobalLayoutListener);
+        getViewTreeObserver().removeOnScrollChangedListener(mOnScrollChangedListener);
+    }
+}

chrome/android/java/src/org/chromium/chrome/browser/signin/SigninView.java

+// Copyright 2018 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.signin;
+
+import android.content.Context;
+import android.support.annotation.Nullable;
+import android.util.AttributeSet;
+import android.view.View;
+import android.widget.Button;
+import android.widget.LinearLayout;
+
+import org.chromium.chrome.R;
+import org.chromium.ui.widget.ButtonCompat;
+
+/** View that wraps signin screen and caches references to UI elements. */
+public class SigninView extends LinearLayout {
+    private SigninScrollView mScrollView;
+    private ButtonCompat mAcceptButton;
+    private Button mRefuseButton;
+    private Button mMoreButton;
+    private View mAcceptButtonEndPadding;
+
+    public SigninView(Context context, @Nullable AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    @Override
+    protected void onFinishInflate() {
+        super.onFinishInflate();
+
+        mScrollView = (SigninScrollView) findViewById(R.id.signin_scroll_view);
+        mAcceptButton = (ButtonCompat) findViewById(R.id.positive_button);
+        mRefuseButton = (Button) findViewById(R.id.negative_button);
+        mMoreButton = (Button) findViewById(R.id.more_button);
+        mAcceptButtonEndPadding = findViewById(R.id.positive_button_end_padding);
+    }
+
+    public SigninScrollView getScrollView() {
+        return mScrollView;
+    }
+
+    public ButtonCompat getAcceptButton() {
+        return mAcceptButton;
+    }
+
+    public Button getRefuseButton() {
+        return mRefuseButton;
+    }
+
+    public Button getMoreButton() {
+        return mMoreButton;
+    }
+
+    public View getAcceptButtonEndPadding() {
+        return mAcceptButtonEndPadding;
+    }
+}

chrome/android/java/strings/android_chrome_strings.grd

@@ -2296,7 +2296,13 @@ To obtain new licenses, connect to the internet and play your downloaded content
         Waiting for Google Play Services to finish updating
       </message>
 
-      <!-- New Signin Promos Strings -->
+      <!-- Strings for Streamlined Signin and Unified Consent. -->
+      <!-- TODO(https://crbug.com/814728): Make translatable when strings are approved. -->
+      <message name="IDS_SIGNIN_ACCEPT_BUTTON" desc="Text for the confirmation button in the sign-in screen. By clicking this button users signs in and turns on Sync and personalization. [CHAR-LIMIT=20]" translateable="false">
+        Yes, I'm in
+      </message>
+
+      <!-- Personalized Signin Promos Strings -->
       <message name="IDS_SIGNIN_PROMO_DESCRIPTION_BOOKMARKS" desc="Description string for 'Continue as' signin promo shown in Bookmarks screen.">
         To get your bookmarks on all your devices, sign in to Chrome.
       </message>

chrome/android/java_sources.gni

@@ -1120,6 +1120,8 @@ chrome_java_sources = [
   "java/src/org/chromium/chrome/browser/signin/SigninManager.java",
   "java/src/org/chromium/chrome/browser/signin/SigninPromoController.java",
   "java/src/org/chromium/chrome/browser/signin/SigninPromoUtil.java",
+  "java/src/org/chromium/chrome/browser/signin/SigninScrollView.java",
+  "java/src/org/chromium/chrome/browser/signin/SigninView.java",
   "java/src/org/chromium/chrome/browser/signin/SyncPromoView.java",
   "java/src/org/chromium/chrome/browser/snackbar/BottomContainer.java",
   "java/src/org/chromium/chrome/browser/snackbar/DataReductionPromoSnackbarController.java",