Fix a bug that some NativePage might overlap tabstrip on tablets

chrome/android/java/src/org/chromium/chrome/browser/tab/TabContentViewParent.java

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.tab;
 
 import android.content.Context;
 import android.support.design.widget.CoordinatorLayout;
 import android.support.design.widget.CoordinatorLayout.Behavior;
+import android.view.Gravity;
 import android.view.View;
 import android.widget.FrameLayout;
 
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.banners.SwipableOverlayView;
 import org.chromium.ui.UiUtils;
 import org.chromium.ui.base.DeviceFormFactor;
 
 /**
  * Parent {@link FrameLayout} holding the infobar and content of a tab. The content could be either
@@ skipping 16 matching lines @@
             if (tab.getNativePage() != null) {
                 viewToShow = tab.getNativePage().getView();
                 if (isShowing(viewToShow)) return;
 
             } else {
                 viewToShow = tab.getContentViewCore().getContainerView();
                 if (isShowing(viewToShow)) return;
             }
 
             removeCurrentContent();
+            LayoutParams lp = (LayoutParams) viewToShow.getLayoutParams();
+            if (lp == null) {
+                lp = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
+            }
+            // Weirdly enough, if gravity is not top, top_margin is not respected by FrameLayout.
+            // Yet for many native pages on tablet, top_margin is necessary to not overlap the tab
+            // switcher.
+            lp.gravity = Gravity.TOP;
             UiUtils.removeViewFromParent(viewToShow);
-            addView(viewToShow, CONTENT_INDEX, new FrameLayout.LayoutParams(
-                    LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
+            addView(viewToShow, CONTENT_INDEX, lp);
             viewToShow.requestFocus();
         }
     };
 
     public TabContentViewParent(Context context, Tab tab) {
         super(context);
         mInfobarWrapper = new FrameLayout(context);
         mInfobarWrapper.setFocusable(true);
         mInfobarWrapper.setFocusableInTouchMode(true);
         addView(mInfobarWrapper,
@@ skipping 51 matching lines @@
             return true;
         }
 
         @Override
         public void onDependentViewRemoved(CoordinatorLayout parent, TabContentViewParent child,
                 View dependency) {
             child.mInfobarWrapper.setTranslationY(0);
         }
     }
 }