Hold a reference to any kind of context in WindowAndroid.

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 3d775de11c9f19e5be9260380f87fbb609a9f2fa..3634df8234a3a38a951bca8053f816f63cd95a21 100644
--- a/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
+++ b/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
@@ -77,6 +77,10 @@ public class WindowAndroid {
 
     protected Context mApplicationContext;
     protected SparseArray<IntentCallback> mOutstandingIntents;
+    // To render properly on an external display through a Presentation we need to fetch
+    // display metrics from the context provided by the Presentation. This context is not the same
+    // as the application context since the application context targets the primary display.
+    protected WeakReference<Context> mDisplayContextRef;

[boliu, 2015/10/21 16:55:38]

private?

Explain this needs to be a weakreference to prevent leaks in webview

[gsennton, 2015/10/23 16:27:07]

Done.

 
     // 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
@@ -136,13 +140,14 @@ public class WindowAndroid {
      */
     @SuppressLint("UseSparseArrays")
     public WindowAndroid(Context context) {
-        assert context == context.getApplicationContext();
-        mApplicationContext = context;
+        mApplicationContext = context.getApplicationContext();
+        // context could be an Activity Context so we can't hold a strong reference to it.
+        mDisplayContextRef = new WeakReference<Context>(context);
         mOutstandingIntents = new SparseArray<IntentCallback>();
         mIntentErrors = new HashMap<Integer, String>();
         mVSyncMonitor = new VSyncMonitor(context, mVSyncListener);
-        mAccessibilityManager = (AccessibilityManager)
-                context.getSystemService(Context.ACCESSIBILITY_SERVICE);
+        mAccessibilityManager = (AccessibilityManager) mApplicationContext.getSystemService(
+                Context.ACCESSIBILITY_SERVICE);
     }
 
     /**
@@ -583,6 +588,11 @@ public class WindowAndroid {
         });
     }
 
+    @CalledByNative
+    private 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