Update WebView visibility during attach/detach

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 8ad3b4597e88892494eeef7fda2bebd8cf853ecb..70ebbd001fbc20bb6791c32560cf0f3ed8fc7f3b 100644
--- a/android_webview/java/src/org/chromium/android_webview/AwContents.java
+++ b/android_webview/java/src/org/chromium/android_webview/AwContents.java
@@ -972,7 +972,7 @@ public class AwContents implements SmartClipProvider,
         installWebContentsObserver();
         mSettings.setWebContents(webContents);
         nativeSetDipScale(mNativeAwContents, (float) mDIPScale);
-        updateContentViewCoreVisibility();
+        postUpdateContentViewCoreVisibility();
 
         // The native side object has been bound to this java instance, so now is the time to
         // bind all the native->java relationships.
@@ -1798,7 +1798,7 @@ public class AwContents implements SmartClipProvider,
         if (mIsPaused || isDestroyed(NO_WARN)) return;
         mIsPaused = true;
         nativeSetIsPaused(mNativeAwContents, mIsPaused);
-        updateContentViewCoreVisibility();
+        postUpdateContentViewCoreVisibility();
     }
 
     /**
@@ -1809,7 +1809,7 @@ public class AwContents implements SmartClipProvider,
         if (!mIsPaused || isDestroyed(NO_WARN)) return;
         mIsPaused = false;
         nativeSetIsPaused(mNativeAwContents, mIsPaused);
-        updateContentViewCoreVisibility();
+        postUpdateContentViewCoreVisibility();
     }
 
     /**
@@ -2348,7 +2348,7 @@ public class AwContents implements SmartClipProvider,
     private void setViewVisibilityInternal(boolean visible) {
         mIsViewVisible = visible;
         if (!isDestroyed(NO_WARN)) nativeSetViewVisibility(mNativeAwContents, mIsViewVisible);
-        updateContentViewCoreVisibility();
+        postUpdateContentViewCoreVisibility();
     }
 
     private void setWindowVisibilityInternal(boolean visible) {
@@ -2356,7 +2356,22 @@ public class AwContents implements SmartClipProvider,
                 && visible && !mIsWindowVisible;
         mIsWindowVisible = visible;
         if (!isDestroyed(NO_WARN)) nativeSetWindowVisibility(mNativeAwContents, mIsWindowVisible);
-        updateContentViewCoreVisibility();
+        postUpdateContentViewCoreVisibility();
+    }
+
+    private void postUpdateContentViewCoreVisibility() {
+        // When WebView is attached to a visible window, WebView will be
+        // attached to a window whose visibility is initially invisible, then
+        // the window visibility will be updated to true. This means CVC
+        // visibility will be set to false then true immediately, in the same
+        // function call of View#dispatchAttachedToWindow. To prevent this flip
+        // of CVC visibility, post the task to update CVC visibility.
+        mHandler.post(new Runnable() {

[boliu, 2015/11/03 22:05:46]

Can you not post more than you need to?

Also don't re-allocate new runnable every time. Save it in an instance variable,
and maybe allocate it lazily. (To avoid gc churn)

+            @Override
+            public void run() {
+                updateContentViewCoreVisibility();
+            }
+        });
     }
 
     private void updateContentViewCoreVisibility() {
@@ -3005,6 +3020,7 @@ public class AwContents implements SmartClipProvider,
             nativeOnAttachedToWindow(mNativeAwContents, mContainerView.getWidth(),
                     mContainerView.getHeight());
             updateHardwareAcceleratedFeaturesToggle();
+            postUpdateContentViewCoreVisibility();
 
             setLocale(LocaleUtils.getDefaultLocale());
 
@@ -3026,6 +3042,7 @@ public class AwContents implements SmartClipProvider,
 
             mContentViewCore.onDetachedFromWindow();
             updateHardwareAcceleratedFeaturesToggle();
+            postUpdateContentViewCoreVisibility();
 
             if (mComponentCallbacks != null) {
                 mContext.unregisterComponentCallbacks(mComponentCallbacks);