Expose WindowAndroid from WebContents.

chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java b/chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java
index 334846859329b66dd707f5da1628e8b8b2defef1..a24fcb514680ab9d0314342c1e581075c42f0f7e 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java
@@ -2059,10 +2059,7 @@ public abstract class ChromeActivity extends AsyncInitializationActivity
     @Nullable public static ChromeActivity fromWebContents(@Nullable WebContents webContents) {
         if (webContents == null) return null;
 
-        ContentViewCore contentViewCore = ContentViewCore.fromWebContents(webContents);
-        if (contentViewCore == null) return null;
-
-        WindowAndroid window = contentViewCore.getWindowAndroid();
+        WindowAndroid window = webContents.getTopLevelNativeWindow();
         if (window == null) return null;
 
         Activity activity = window.getActivity().get();