diff -r 000000000000 -r 6474c204b198 mobile/android/base/toolbar/BackButton.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mobile/android/base/toolbar/BackButton.java	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,96 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.toolbar;
+
+import org.mozilla.gecko.R;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.LinearGradient;
+import android.graphics.Paint;
+import android.graphics.Path;
+import android.graphics.Shader;
+import android.graphics.drawable.Drawable;
+import android.graphics.drawable.StateListDrawable;
+import android.util.AttributeSet;
+
+public class BackButton extends ShapedButton { 
+    private Path mPath;
+    private Path mBorderPath;
+    private Paint mBorderPaint;
+    private Paint mBorderPrivatePaint;
+
+    public BackButton(Context context, AttributeSet attrs) {
+        super(context, attrs);
+
+        // Paint to draw the border.
+        mBorderPaint = new Paint();
+        mBorderPaint.setAntiAlias(true);
+        mBorderPaint.setColor(0xFF000000);
+        mBorderPaint.setStyle(Paint.Style.STROKE);
+
+        mBorderPrivatePaint = new Paint(mBorderPaint);
+
+        // Path is masked.
+        mPath = new Path();
+        mBorderPath = new Path();
+    }
+
+    @Override
+    protected void onSizeChanged(int width, int height, int oldWidth, int oldHeight) {
+        super.onSizeChanged(width, height, oldWidth, oldHeight);
+
+        mPath.reset();
+        mPath.addCircle(width/2, height/2, width/2, Path.Direction.CW);
+
+        float borderWidth = getContext().getResources().getDimension(R.dimen.nav_button_border_width);
+        mBorderPaint.setStrokeWidth(borderWidth);
+        mBorderPrivatePaint.setStrokeWidth(borderWidth);
+
+        mBorderPath.reset();
+        mBorderPath.addCircle(width/2, height/2, (width/2) - borderWidth, Path.Direction.CW);
+
+        mBorderPaint.setShader(new LinearGradient(0, 0, 
+                                                  0, height, 
+                                                  0xFFB5BBC1, 0xFFFAFBFC,
+                                                  Shader.TileMode.CLAMP));
+
+        mBorderPrivatePaint.setShader(new LinearGradient(0, 0, 
+                                                         0, height, 
+                                                         0xFF040607, 0xFF0B0D0E,
+                                                         Shader.TileMode.CLAMP));
+    }
+
+    @Override
+    public void draw(Canvas canvas) {
+        mCanvasDelegate.draw(canvas, mPath, getWidth(), getHeight());
+
+        // Draw the border on top.
+        canvas.drawPath(mBorderPath, isPrivateMode() ? mBorderPrivatePaint : mBorderPaint);
+    }
+
+    // The drawable is constructed as per @drawable/url_bar_nav_button.
+    @Override
+    public void onLightweightThemeChanged() {
+        final Drawable drawable = mTheme.getDrawable(this);
+        if (drawable == null)
+            return;
+
+        final StateListDrawable stateList = new StateListDrawable();
+        stateList.addState(PRIVATE_PRESSED_STATE_SET, getColorDrawable(R.color.highlight_nav_pb));
+        stateList.addState(PRESSED_ENABLED_STATE_SET, getColorDrawable(R.color.highlight_nav));
+        stateList.addState(PRIVATE_FOCUSED_STATE_SET, getColorDrawable(R.color.highlight_nav_focused_pb));
+        stateList.addState(FOCUSED_STATE_SET, getColorDrawable(R.color.highlight_nav_focused));
+        stateList.addState(PRIVATE_STATE_SET, getColorDrawable(R.color.background_private));
+        stateList.addState(EMPTY_STATE_SET, drawable);
+
+        setBackgroundDrawable(stateList);
+    }
+
+    @Override
+    public void onLightweightThemeReset() {
+        setBackgroundResource(R.drawable.url_bar_nav_button);
+    }
+}