Make ActivityWindowAndroid per-activity

android_webview/java/src/org/chromium/android_webview/AwContents.java

Index: android_webview/java/src/org/chromium/android_webview/AwContents.java
diff --git a/android_webview/java/src/org/chromium/android_webview/AwContents.java b/android_webview/java/src/org/chromium/android_webview/AwContents.java
index 0a0e8530776bffcb7df689bea0ff2b19e862f171..972360b86b6aeb3b246e46e78ee7e81f7d1eb518 100644
--- a/android_webview/java/src/org/chromium/android_webview/AwContents.java
+++ b/android_webview/java/src/org/chromium/android_webview/AwContents.java
@@ -77,6 +77,7 @@ import java.net.URL;
 import java.util.HashMap;
 import java.util.Locale;
 import java.util.Map;
+import java.util.WeakHashMap;
 import java.util.concurrent.Callable;
 
 /**
@@ -207,7 +208,7 @@ public class AwContents implements SmartClipProvider,
     private final Context mContext;
     private final int mAppTargetSdkVersion;
     private ContentViewCore mContentViewCore;
-    private WindowAndroid mWindowAndroid;
+    private WindowAndroidWrapper mWindowAndroid;
     private WebContents mWebContents;
     private NavigationController mNavigationController;
     private final AwContentsClient mContentsClient;
@@ -287,16 +288,13 @@ public class AwContents implements SmartClipProvider,
 
     private static final class DestroyRunnable implements Runnable {
         private final long mNativeAwContents;
-        private final WindowAndroid mWindowAndroid;
 
-        private DestroyRunnable(long nativeAwContents, WindowAndroid windowAndroid) {
+        private DestroyRunnable(long nativeAwContents) {
             mNativeAwContents = nativeAwContents;
-            mWindowAndroid = windowAndroid;
         }
         @Override
         public void run() {
             nativeDestroy(mNativeAwContents);
-            mWindowAndroid.destroy();
         }
     }
 
@@ -848,6 +846,60 @@ public class AwContents implements SmartClipProvider,
         mContainerView.requestLayout();
     }
 
+    // This class destroys the WindowAndroid when after it is gc-ed.
+    private static class WindowAndroidWrapper {
+        private final WindowAndroid mWindowAndroid;
+        private final CleanupReference mCleanupReference;
+
+        private static final class DestroyRunnable implements Runnable {
+            private final WindowAndroid mWindowAndroid;
+            private DestroyRunnable(WindowAndroid windowAndroid) {
+                mWindowAndroid = windowAndroid;
+            }
+            @Override
+            public void run() {
+                mWindowAndroid.destroy();
+            }
+        }
+
+        public WindowAndroidWrapper(WindowAndroid windowAndroid) {
+            mWindowAndroid = windowAndroid;
+            mCleanupReference =
+                    new CleanupReference(this, new DestroyRunnable(windowAndroid));
+        }
+
+        public WindowAndroid getWindowAndroid() {
+            return mWindowAndroid;
+        }
+    }
+    private static WindowAndroidWrapper sCachedWindowAndroid;
+    private static WeakHashMap<Activity, WindowAndroidWrapper> sActivityWindowMap;

[Torne, 2015/05/15 12:48:13]

The hash map won't release the WindowAndroidWrapper until the activity is GCed,
even if there is no AwContents left which references the WindowAndroidWrapper.
Do we care if the ActivityWindowAndroid always lives as long as the Activity,
even when there's no WebView currently in existence? Probably fine..

[boliu, 2015/05/15 13:34:01]

Yeah I think that's fine. If another webview is created in the same activity,
the ActivityWindowAndroid will be reused, so it's not really "leaking".

+
+    // getWindowAndroid is only called on UI thread, so there are no threading issues with lazy
+    // initialization.
+    @SuppressFBWarnings("LI_LAZY_INIT_STATIC")
+    private static WindowAndroidWrapper getWindowAndroid(Context context) {
+        // TODO(boliu): WebView does not currently initialize ApplicationStatus, crbug.com/470582.
+        Activity activity = ContentViewCore.activityFromContext(context);
+        if (activity == null) {
+            if (sCachedWindowAndroid == null) {
+                sCachedWindowAndroid = new WindowAndroidWrapper(
+                        new WindowAndroid(context.getApplicationContext()));
+            }
+            return sCachedWindowAndroid;
+        }
+
+        if (sActivityWindowMap == null) sActivityWindowMap = new WeakHashMap<>();
+        WindowAndroidWrapper activityWindowAndroid = sActivityWindowMap.get(activity);
+        if (activityWindowAndroid == null) {
+            final boolean listenToActivityState = false;
+            activityWindowAndroid = new WindowAndroidWrapper(
+                    new ActivityWindowAndroid(activity, listenToActivityState));
+            sActivityWindowMap.put(activity, activityWindowAndroid);
+        }
+        return activityWindowAndroid;
+    }
+
     /* Common initialization routine for adopting a native AwContents instance into this
      * java instance.
      *
@@ -871,15 +923,10 @@ public class AwContents implements SmartClipProvider,
 
         WebContents webContents = nativeGetWebContents(mNativeAwContents);
 
-        // WebView does not currently initialize ApplicationStatus, crbug.com/470582.
-        final boolean listenToActivityState = false;
-        Activity activity = ContentViewCore.activityFromContext(mContext);
-        mWindowAndroid = activity != null
-                ? new ActivityWindowAndroid(activity, listenToActivityState)
-                : new WindowAndroid(mContext.getApplicationContext());
-        mContentViewCore = createAndInitializeContentViewCore(
-                mContainerView, mContext, mInternalAccessAdapter, webContents,
-                new AwGestureStateListener(), mContentViewClient, mZoomControls, mWindowAndroid);
+        mWindowAndroid = getWindowAndroid(mContext);
+        mContentViewCore = createAndInitializeContentViewCore(mContainerView, mContext,
+                mInternalAccessAdapter, webContents, new AwGestureStateListener(),
+                mContentViewClient, mZoomControls, mWindowAndroid.getWindowAndroid());
         nativeSetJavaPeers(mNativeAwContents, this, mWebContentsDelegate, mContentsClientBridge,
                 mIoThreadClient, mInterceptNavigationDelegate);
         mWebContents = mContentViewCore.getWebContents();
@@ -892,7 +939,7 @@ public class AwContents implements SmartClipProvider,
         // The native side object has been bound to this java instance, so now is the time to
         // bind all the native->java relationships.
         mCleanupReference =
-                new CleanupReference(this, new DestroyRunnable(mNativeAwContents, mWindowAndroid));
+                new CleanupReference(this, new DestroyRunnable(mNativeAwContents));
     }
 
     private void installWebContentsObserver() {
@@ -2452,7 +2499,7 @@ public class AwContents implements SmartClipProvider,
 
     @CalledByNative
     private void postInvalidateOnAnimation() {
-        if (!mWindowAndroid.isInsideVSync()) {
+        if (!mWindowAndroid.getWindowAndroid().isInsideVSync()) {
             mContainerView.postInvalidateOnAnimation();
         } else {
             mContainerView.invalidate();