Peek new infobars behind existing ones

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

Index: chrome/android/java/res/layout/main.xml
diff --git a/chrome/android/java/res/layout/main.xml b/chrome/android/java/res/layout/main.xml
index 89c0c32936ad9ceae88dd100f42df2a74f1db7b1..807220aa656d691caed981f88999428961426352 100644
--- a/chrome/android/java/res/layout/main.xml
+++ b/chrome/android/java/res/layout/main.xml
@@ -24,7 +24,8 @@
                 android:id="@+id/bottom_container"
                 android:layout_width="match_parent"
                 android:layout_height="match_parent"
-                android:layout_gravity="start|bottom" />
+                android:layout_gravity="start|bottom"
+                android:clipChildren="false" />

[Ted C, 2017/05/17 17:55:54]

I think we should conditionally set this.  I have a strong suspicion that
Android would have to disable some optimizations with this enabled.

[mdjones, 2017/05/17 21:05:19]

I changed this to be set based on whether the infobar container is running an
animation. I chose to get the container class by id rather than plumbing it
down; I can go this route if you prefer.

 
             <ViewStub
                 android:id="@+id/bottombar_stub"