Some initial changes for manipulating the top controls positions on Android.

content/public/android/java/src/org/chromium/content/browser/ZoomManager.java

 // Copyright (c) 2012 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.content.browser;
 
 import android.content.Context;
 import android.util.Log;
 import android.view.Gravity;
 import android.view.MotionEvent;
@@ skipping 127 matching lines @@
         }
     }
 
     // Passes the touch event to ScaleGestureDetector so that its internal state
     // won't go wrong. ScaleGestureDetector needs two pointers in a MotionEvent
     // to recognize a zoom gesture.
     boolean processTouchEvent(MotionEvent event) {
         // TODO: Need to deal with multi-touch transition
         mMultiTouchListener.setTemporarilyIgnoreDetectorEvents(false);
         try {
-            return mMultiTouchDetector.onTouchEvent(event);
+            boolean inGesture = isScaleGestureDetectionInProgress();
+            boolean retVal = mMultiTouchDetector.onTouchEvent(event);
+            if (event.getActionMasked() == MotionEvent.ACTION_UP && !inGesture) return false;
+            return retVal;
         } catch (Exception e) {
             Log.e(TAG, "ScaleGestureDetector got into a bad state!", e);
             assert(false);
         }
         return false;
     }
 
     void updateMultiTouchSupport() {
         mMultiTouchListener.setPermanentlyIgnoreDetectorEvents(
             !mContentViewCore.getContentSettings().supportsMultiTouchZoom());
@@ skipping 51 matching lines @@
             if (zoomIn) {
                 mContentViewCore.zoomIn();
             } else {
                 mContentViewCore.zoomOut();
             }
             // ContentView will call updateZoomControls after its current page scale
             // is got updated from the native code.
         }
     }
 }