[Android] Fix flashing ripple on tab switch toolbar button

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

Index: chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarPhone.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarPhone.java b/chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarPhone.java
index 6cd6e19e0a03ae45952c97e54015218abffe12f1..328bb774e7df35d198cc6b63e48f992129025e3e 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarPhone.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarPhone.java
@@ -28,6 +28,7 @@
 import android.support.v4.view.animation.FastOutSlowInInterpolator;
 import android.util.AttributeSet;
 import android.util.Property;
+import android.util.TypedValue;
 import android.view.Gravity;
 import android.view.MotionEvent;
 import android.view.View;
@@ -1465,6 +1466,7 @@ private void updateViewsForTabSwitcherMode() {
 
         updateProgressBarVisibility();
         updateVisualsForToolbarState();
+        updateTabSwitcherButtonRipple();
     }
 
     private void updateProgressBarVisibility() {
@@ -1527,6 +1529,22 @@ protected void setTabSwitcherMode(
         postInvalidateOnAnimation();
     }
 
+    /**
+     * Enables or disables the tab switcher ripple depending on whether we are in or out of the tab
+     * switcher mode.
+     */
+    private void updateTabSwitcherButtonRipple() {
+        if (mTabSwitcherState == ENTERING_TAB_SWITCHER) {
+            mToggleTabStackButton.setBackgroundColor(
+                    ApiCompatibilityUtils.getColor(getResources(), android.R.color.transparent));
+        } else {
+            TypedValue outValue = new TypedValue();
+            // the linked style here will have to be changed if it is updated in the XML.
+            getContext().getTheme().resolveAttribute(R.style.ToolbarButton, outValue, true);
+            mToggleTabStackButton.setBackgroundResource(outValue.resourceId);
+        }
+    }
+
     @Override
     protected void onTabSwitcherTransitionFinished() {
         setAlpha(1.f);