[NTP Button] Adds variation-specific icons

Bug: 843639
Change-Id: I16a97d38c35071aee6b5c94874b74f7e986f47f2
Reviewed-on: https://chromium-review.googlesource.com/1072038
Commit-Queue: Daniel Park <danielpark@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Cr-Commit-Position: refs/heads/master@{#561860}

chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarLayout.java

@@ -13,6 +13,7 @@ import android.graphics.Canvas;
 import android.graphics.Rect;
 import android.graphics.drawable.Drawable;
 import android.os.SystemClock;
+import android.text.TextUtils;
 import android.util.AttributeSet;
 import android.view.InputDevice;
 import android.view.MotionEvent;
@@ -964,4 +965,27 @@ public abstract class ToolbarLayout extends FrameLayout implements Toolbar {
         return VariationsAssociatedData.getVariationParamValue(
                 NTP_BUTTON_TRIAL_NAME, NTP_BUTTON_VARIATION_PARAM_NAME);
     }
+
+    protected void changeIconToNTPIcon(TintedImageButton ntpButton) {
+        String variation = getNTPButtonVariation();
+        if (TextUtils.isEmpty(variation)) return;
+
+        int iconResId = 0;
+        switch (variation) {
+            case "home":
+                iconResId = R.drawable.ic_home;
+                break;
+            case "news_feed":
+                iconResId = R.drawable.ic_library_news_feed;
+                break;
+            case "chrome":
+                iconResId = R.drawable.ic_chrome;
+                break;
+            default:
+                break;
+        }
+        assert iconResId != 0;
+
+        ntpButton.setImageResource(iconResId);
+    }
 }

chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarPhone.java

@@ -366,6 +366,7 @@ public class ToolbarPhone extends ToolbarLayout
         mToolbarButtonsContainer = (ViewGroup) findViewById(R.id.toolbar_buttons);
 
         mHomeButton = (TintedImageButton) findViewById(R.id.home_button);
+        if (FeatureUtilities.isNewTabPageButtonEnabled()) changeIconToNTPIcon(mHomeButton);
 
         mUrlBar = (TextView) findViewById(R.id.url_bar);
 

chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarTablet.java

@@ -129,6 +129,8 @@ public class ToolbarTablet
         mShouldAnimateButtonVisibilityChange = false;
         mToolbarButtonsVisible = true;
         mToolbarButtons = new TintedImageButton[] {mBackButton, mForwardButton, mReloadButton};
+
+        if (FeatureUtilities.isNewTabPageButtonEnabled()) changeIconToNTPIcon(mHomeButton);
     }
 
     @Override