Hide fullscreen rotation jank

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

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.tab;
 
 import android.annotation.SuppressLint;
 import android.app.Activity;
 import android.app.Application;
 import android.content.Context;
@@ skipping 891 matching lines @@
     /**
      * @return The background color of the tab.
      */
     public int getBackgroundColor() {
         if (mNativePage != null) return mNativePage.getBackgroundColor();
         if (getWebContents() != null) return getWebContents().getBackgroundColor();
         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.
      */
     public int getThemeColor() {
         return mThemeColor;
     }
 
     /**
      * Calculate the theme color based on if the page is native, the theme color changed, etc.
      * @param didWebContentsThemeColorChange If the theme color of the web contents is known to have
@@ skipping 2205 matching lines @@
     private native long nativeGetBookmarkId(long nativeTabAndroid, boolean onlyEditable);
     private native void nativeSetInterceptNavigationDelegate(long nativeTabAndroid,
             InterceptNavigationDelegate delegate);
     private native void nativeAttachToTabContentManager(long nativeTabAndroid,
             TabContentManager tabContentManager);
     private native boolean nativeHasPrerenderedUrl(long nativeTabAndroid, String url);
     private native void nativeSetWebappManifestScope(long nativeTabAndroid, String scope);
     private native void nativeEnableEmbeddedMediaExperience(long nativeTabAndroid, boolean enabled);
     private native void nativeAttachDetachedTab(long nativeTabAndroid);
 }