Disable double tap zoom on mobile sites, to remove 300ms click delay

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

 // Copyright 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.app.Activity;
 import android.app.SearchManager;
 import android.content.ContentResolver;
 import android.content.Context;
@@ skipping 1478 matching lines @@
     }
 
     @Override
     public boolean didUIStealScroll(float x, float y) {
         return getContentViewClient().shouldOverrideScroll(
                 x, y, computeHorizontalScrollOffset(), computeVerticalScrollOffset());
     }
 
     private void onRenderCoordinatesUpdated() {
         if (mContentViewGestureHandler == null) return;
-        mContentViewGestureHandler.updateHasFixedPageScale(mRenderCoordinates.hasFixedPageScale());
+
+        // We disable double tap zoom for pages that have a width=device-width
+        // or narrower viewport (indicating that this is a mobile-optimized or
+        // responsive web design, so text will be legible without zooming).
+        // We also disable it for pages that disallow the user from zooming in
+        // or out (even if they don't have a device-width or narrower viewport).
+        mContentViewGestureHandler.updateShouldDisableDoubleTap(
+                mRenderCoordinates.hasMobileViewport() || mRenderCoordinates.hasFixedPageScale());
     }
 
     private void hidePopupDialog() {
         SelectPopupDialog.hide(this);
         hideHandles();
         hideSelectActionBar();
     }
 
     void hideSelectActionBar() {
         if (mActionMode != null) {
@@ skipping 1852 matching lines @@
 
     private native void nativeAttachExternalVideoSurface(
             int nativeContentViewCoreImpl, int playerId, Surface surface);
 
     private native void nativeDetachExternalVideoSurface(
             int nativeContentViewCoreImpl, int playerId);
 
     private native void nativeSetAccessibilityEnabled(
             int nativeContentViewCoreImpl, boolean enabled);
 }