Hide fullscreen rotation jank

chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java

Index: chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java b/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
index 4de80857dfe2c5b01b3c8c3b19c9c5417292af97..bd202a58e3a90ed724ae3a1460a07dae29e16255 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
@@ -908,6 +908,14 @@ public class Tab
         return Color.WHITE;
     }
 
+    /**
+     * @return Whether or not the tab can show the static layer.
+     */
+    public boolean canUseStaticLayer() {

[aelias_OOO_until_Jul13, 2017/06/16 22:46:40]

This whole canUseStaticLayer thing seems to be unused.  Looks like a legacy of
an obsolete patchset, please delete it.

[steimel, 2017/06/16 23:24:12]

It's actually used to plumb that bool out to ContentLayer to tell it to not show
the static/thumbnail layer when we're trying to show a black frame:
https://codereview.chromium.org/2810813004/diff/220001/chrome/browser/android...

[aelias_OOO_until_Jul13, 2017/06/17 01:18:34]

OK, I guess live_layer_draws is false because it was detached.  How about
calling ThumbnailCache::Remove() when entering fullscreen instead?  It won't
repopulate it from the disk cache because it's the primary tab.

[steimel, 2017/06/20 21:28:35]

Done and will be included in next patch

+        if (getWebContents() != null) return getWebContents().canShowThumbnailPlaceholder();
+        return true;
+    }
+
     /**
      * @return The current theme color based on the value passed from the web contents and the
      *         security state.