From 5f1c549132150c85edfa8982c4da5c0fd41d8919 Mon Sep 17 00:00:00 2001
From: John Reck <jreck@google.com>
Date: Wed, 9 Nov 2011 16:23:07 -0800
Subject: [PATCH] Pause drawing when not visible

 Bug: 5594608
 If onPause is called or if the view or view's window is no longer
 visible, pause webview drawing. Calls to onDraw will continue to work,
 but animations and other continual drawing will stop

Change-Id: I11640f087852d1a9a33b945ff72297fab1d25b94
---
 core/java/android/webkit/WebView.java | 28 +++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/core/java/android/webkit/WebView.java b/core/java/android/webkit/WebView.java
index 35efabcb6d816..c8f027040d0ef 100644
--- a/core/java/android/webkit/WebView.java
+++ b/core/java/android/webkit/WebView.java
@@ -3254,6 +3254,26 @@ public class WebView extends AbsoluteLayout
             if (mHTML5VideoViewProxy != null) {
                 mHTML5VideoViewProxy.pauseAndDispatch();
             }
+            if (mNativeClass != 0) {
+                nativeSetPauseDrawing(mNativeClass, true);
+            }
+        }
+    }
+
+    @Override
+    protected void onWindowVisibilityChanged(int visibility) {
+        super.onWindowVisibilityChanged(visibility);
+        updateDrawingState();
+    }
+
+    void updateDrawingState() {
+        if (mNativeClass == 0 || mIsPaused) return;
+        if (getWindowVisibility() != VISIBLE) {
+            nativeSetPauseDrawing(mNativeClass, true);
+        } else if (getVisibility() != VISIBLE) {
+            nativeSetPauseDrawing(mNativeClass, true);
+        } else {
+            nativeSetPauseDrawing(mNativeClass, false);
         }
     }
 
@@ -3265,6 +3285,9 @@ public class WebView extends AbsoluteLayout
         if (mIsPaused) {
             mIsPaused = false;
             mWebViewCore.sendMessage(EventHub.ON_RESUME);
+            if (mNativeClass != 0) {
+                nativeSetPauseDrawing(mNativeClass, false);
+            }
         }
     }
 
@@ -5599,6 +5622,7 @@ public class WebView extends AbsoluteLayout
         if (visibility != View.VISIBLE && mZoomManager != null) {
             mZoomManager.dismissZoomPicker();
         }
+        updateDrawingState();
     }
 
     /**
@@ -8403,6 +8427,9 @@ public class WebView extends AbsoluteLayout
                         setNewPicture(mDelaySetPicture, true);
                         mDelaySetPicture = null;
                     }
+                    if (mIsPaused) {
+                        nativeSetPauseDrawing(mNativeClass, true);
+                    }
                     break;
                 case UPDATE_TEXTFIELD_TEXT_MSG_ID:
                     // Make sure that the textfield is currently focused
@@ -9584,4 +9611,5 @@ public class WebView extends AbsoluteLayout
      * See {@link ComponentCallbacks2} for the trim levels and descriptions
      */
     private static native void     nativeOnTrimMemory(int level);
+    private static native void nativeSetPauseDrawing(int instance, boolean pause);
 }