Make WebView work for external displays (over Presentations).

ui/android/java/src/org/chromium/ui/base/WindowAndroid.java

Index: ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
diff --git a/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java b/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
index 27579e6e3ad4a3888f486f246f4f13e1c17e0c20..43091e9f2f6dd9a485474703c5e2db9df14f8e7a 100644
--- a/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
+++ b/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
@@ -76,6 +76,7 @@ public class WindowAndroid {
 
     protected Context mApplicationContext;
     protected SparseArray<IntentCallback> mOutstandingIntents;
+    protected WeakReference<Context> mDisplayContextRef;
 
     // Ideally, this would be a SparseArray<String>, but there's no easy way to store a
     // SparseArray<String> in a bundle during saveInstanceState(). So we use a HashMap and suppress
@@ -131,12 +132,13 @@ public class WindowAndroid {
      * @param context The application context.
      */
     @SuppressLint("UseSparseArrays")
-    public WindowAndroid(Context context) {
+    public WindowAndroid(Context context, Context displayContext) {
         assert context == context.getApplicationContext();
         mApplicationContext = context;
+        mDisplayContextRef = new WeakReference<Context>(displayContext);
         mOutstandingIntents = new SparseArray<IntentCallback>();
         mIntentErrors = new HashMap<Integer, String>();
-        mVSyncMonitor = new VSyncMonitor(context, mVSyncListener);
+        mVSyncMonitor = new VSyncMonitor(displayContext, mVSyncListener);
         mAccessibilityManager = (AccessibilityManager)
                 context.getSystemService(Context.ACCESSIBILITY_SERVICE);
     }
@@ -562,6 +564,11 @@ public class WindowAndroid {
         });
     }
 
+    @CalledByNative
+    public Context getDisplayContext() {
+        return mDisplayContextRef.get();
+    }
+
     /**
      * Update whether the placeholder is 'drawn' based on whether an animation is running
      * or touch exploration is enabled - if either of those are true, we call