[Android] Moves Splashscreen showing to WebappActivity#preInflationStartup

Since now layout inflation is delayed for WebappActivity, the
splashscreen should be shown in preInflationStartup instead of
postInflationStartup.

This should fix flickering that may occur on some android devices.

Bug: 855888
Change-Id: Ica4ef8431b67a15ded1c769a50501323dc545bf3
Reviewed-on: https://chromium-review.googlesource.com/1119260
Commit-Queue: Mohamed Heikal <mheikal@chromium.org>
Reviewed-by: Peter Kotwicz <pkotwicz@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572453}

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappActivity.java

@@ -293,11 +293,7 @@ public class WebappActivity extends SingleTabActivity {
     }
 
     private void onLayoutInflated(ViewGroup mainView) {
-        View placeHolderView = new View(this);
-        setContentView(placeHolderView);
-        ViewGroup contentParent = (ViewGroup) placeHolderView.getParent();
-        WarmupManager.transferViewHeirarchy(mainView, contentParent);
-        contentParent.removeView(placeHolderView);
+        mSplashController.setViewHierarchyBelowSplashscreen(mainView);
         onInitialLayoutInflationComplete();
     }
 
@@ -385,6 +381,7 @@ public class WebappActivity extends SingleTabActivity {
         setTitle(mWebappInfo.shortName());
 
         super.preInflationStartup();
+        initializeWebappData();
     }
 
     @Override
@@ -613,7 +610,6 @@ public class WebappActivity extends SingleTabActivity {
 
     @Override
     public void postInflationStartup() {
-        initializeWebappData();
         if (getBrowserSession() != null) mTrustedWebContentProvider.verifyRelationship();
 
         super.postInflationStartup();

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappSplashScreenController.java

@@ -21,6 +21,7 @@ import org.chromium.base.ObserverList;
 import org.chromium.base.TraceEvent;
 import org.chromium.base.VisibleForTesting;
 import org.chromium.chrome.R;
+import org.chromium.chrome.browser.WarmupManager;
 import org.chromium.chrome.browser.compositor.CompositorViewHolder;
 import org.chromium.chrome.browser.metrics.WebApkUma;
 import org.chromium.chrome.browser.metrics.WebappUma;
@@ -110,6 +111,15 @@ class WebappSplashScreenController extends EmptyTabObserver {
         });
     }
 
+    /**
+     * Transfers a {@param viewHierarchy} to the splashscreen's parent view while keeping the
+     * splashscreen on top.
+     */
+    public void setViewHierarchyBelowSplashscreen(ViewGroup viewHierarchy) {
+        WarmupManager.transferViewHeirarchy(viewHierarchy, mParentView);
+        mParentView.bringChildToFront(mSplashScreen);
+    }
+
     /** Should be called once native has loaded. */
     public void onFinishedNativeInit(Tab tab, CompositorViewHolder compositorViewHolder) {
         mNativeLoaded = true;