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

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

Index: content/public/android/java/src/org/chromium/content/browser/ContentViewGestureHandler.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/ContentViewGestureHandler.java b/content/public/android/java/src/org/chromium/content/browser/ContentViewGestureHandler.java
index 5fbdb712b91ad720796602a447406f556a0e78a4..367c45e0893a85fe321d84a7a1c46d5631a7386e 100644
--- a/content/public/android/java/src/org/chromium/content/browser/ContentViewGestureHandler.java
+++ b/content/public/android/java/src/org/chromium/content/browser/ContentViewGestureHandler.java
@@ -86,6 +86,8 @@ class ContentViewGestureHandler implements LongPressDelegate {
     // will be mistakenly fired.
     private boolean mIgnoreSingleTap;
 
+    private boolean mDoubleTapZoomEnabled = true;

[klobag.chromium, 2013/07/10 18:26:21]

This should be set by "mListener instanceof GestureDetector.OnDoubleTapListener"
in initGestureDetectors.

[johnme, 2013/07/10 19:19:16]

Done (though that should always be true, as mListener is always initialized to
be a GestureDetector.SimpleOnGestureListener).

I also made setTestDependencies update this accordingly.

+
     // Does native think we are scrolling?  True from right before we
     // send the first scroll event until the last finger is raised.
     // Call nativeScrollBegin() when setting this to true, and use
@@ -275,11 +277,6 @@ class ContentViewGestureHandler implements LongPressDelegate {
          * Show the zoom picker UI.
          */
         public void invokeZoomPicker();
-
-        /**
-         * @return Whether changing the page scale is not possible on the current page.
-         */
-        public boolean hasFixedPageScale();
     }
 
     ContentViewGestureHandler(
@@ -423,6 +420,11 @@ class ContentViewGestureHandler implements LongPressDelegate {
                             mIgnoreSingleTap = true;
                             return true;
                         }
+
+                        if (!mDoubleTapZoomEnabled && !mLongPressDetector.isInLongPress()) {
+                            return onSingleTapConfirmed(e);
+                        }
+
                         // This is a hack to address the issue where user hovers
                         // over a link for longer than DOUBLE_TAP_TIMEOUT, then
                         // onSingleTapConfirmed() is not triggered. But we still
@@ -438,18 +440,6 @@ class ContentViewGestureHandler implements LongPressDelegate {
                                 }
                                 setClickXAndY((int) x, (int) y);
                                 return true;
-                            } else if (mMotionEventDelegate.hasFixedPageScale()) {
-                                // If page is not user scalable, we don't need to wait
-                                // for double tap timeout.
-                                float x = e.getX();
-                                float y = e.getY();
-                                mExtraParamBundle.clear();
-                                mExtraParamBundle.putBoolean(SHOW_PRESS, mShowPressIsCalled);
-                                if (sendMotionEventAsGesture(GESTURE_SINGLE_TAP_CONFIRMED, e,
-                                        mExtraParamBundle)) {
-                                    mIgnoreSingleTap = true;
-                                }
-                                setClickXAndY((int) x, (int) y);
                             } else {
                                 // Notify Blink about this tapUp event anyway,
                                 // when none of the above conditions applied.
@@ -520,6 +510,23 @@ class ContentViewGestureHandler implements LongPressDelegate {
         }
     }
 
+    public void setDoubleTapZoomEnabled(boolean enable) {
+        if (enable == mDoubleTapZoomEnabled) {
+            return;
+        }
+
+        GestureDetector.OnDoubleTapListener listener = null;
+        if (enable && mListener instanceof GestureDetector.OnDoubleTapListener) {
+            listener = (GestureDetector.OnDoubleTapListener)mListener;
+        }
+        mGestureDetector.setOnDoubleTapListener(listener);
+        mDoubleTapZoomEnabled = enable;
+
+        // Clean up state, in particular, prevent GestureDetector from getting
+        // left with mIsDoubleTapping == true but mDoubleTapListener == null.
+        resetGestureHandlers();
+    }
+
     /**
      * @return LongPressDetector handling setting up timers for and canceling LongPress gestures.
      */