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 44be9d6c3ef729a7307daa1a8f127e7cb85e28d7..3e72c5bcee09059093f22c7d4e9c67105339d7eb 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
@@ -2509,6 +2509,11 @@ public class Tab
             mFullscreenManager.setPersistentFullscreenMode(enableFullscreen);
         }
 
+        // When going into fullscreen, we want to remove any cached thumbnail of the Tab.
+        if (enableFullscreen) {
+            clearThumbnailPlaceholder();
+        }
+
         RewindableIterator<TabObserver> observers = getTabObservers();
         while (observers.hasNext()) {
             observers.next().onToggleFullscreenMode(this, enableFullscreen);
@@ -2542,6 +2547,13 @@ public class Tab
         TabModelImpl.setActualTabSwitchLatencyMetricRequired();
     }
 
+    /**
+     * Clears the cached thumbnail for this Tab.
+     */
+    public void clearThumbnailPlaceholder() {

[Khushal, 2017/07/12 17:15:39]

You don't need this public function. Use the native function directly in
toggleFullscreenMode?

[steimel, 2017/07/12 18:24:21]

Done.

+        if (mNativeTabAndroid != 0) nativeClearThumbnailPlaceholder(mNativeTabAndroid);
+    }
+
     /**
      * Push state about whether or not the browser controls can show or hide to the renderer.
      */
@@ -3133,6 +3145,7 @@ public class Tab
             InterceptNavigationDelegate delegate);
     private native void nativeAttachToTabContentManager(long nativeTabAndroid,
             TabContentManager tabContentManager);
+    private native void nativeClearThumbnailPlaceholder(long nativeTabAndroid);
     private native boolean nativeHasPrerenderedUrl(long nativeTabAndroid, String url);
     private native void nativeSetWebappManifestScope(long nativeTabAndroid, String scope);
     private native void nativeEnableEmbeddedMediaExperience(long nativeTabAndroid, boolean enabled);