If we defer processing the touch events, pass the

original view coordinate with TouchEventData and use
them when we reprocess the events. We can't depend
on contentToView() to convert the doc point to the
view point. When we originally convert the view to
doc, the scroll position in UI doesn't change. When
we convert the doc back to view, we are chasing a
moving target. That is why we saw bigger delta.

Fix  http://b/issue?id=2577274

2 files changed, 33 insertions, 17 deletions

diff --git a/core/java/android/webkit/WebView.java b/core/java/android/webkit/WebView.java
index 06a7a6f..7bd83e7 100644
--- a/core/java/android/webkit/WebView.java
+++ b/core/java/android/webkit/WebView.java
@@ -4659,13 +4659,16 @@ public class WebView extends AbsoluteLayout
                         ted.mY = contentY;
                         ted.mMetaState = ev.getMetaState();
                         ted.mReprocess = mDeferTouchProcess;
-                        mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
                         if (mDeferTouchProcess) {
                             // still needs to set them for compute deltaX/Y
                             mLastTouchX = x;
                             mLastTouchY = y;
+                            ted.mViewX = x;
+                            ted.mViewY = y;
+                            mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
                             break;
                         }
+                        mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
                         if (!inFullScreenMode()) {
                             mPrivateHandler.sendMessageDelayed(mPrivateHandler
                                     .obtainMessage(PREVENT_DEFAULT_TIMEOUT,
@@ -4691,17 +4694,20 @@ public class WebView extends AbsoluteLayout
                 // pass the touch events from UI thread to WebCore thread
                 if (shouldForwardTouchEvent() && mConfirmMove && (firstMove
                         || eventTime - mLastSentTouchTime > mCurrentTouchInterval)) {
+                    mLastSentTouchTime = eventTime;
                     TouchEventData ted = new TouchEventData();
                     ted.mAction = action;
                     ted.mX = contentX;
                     ted.mY = contentY;
                     ted.mMetaState = ev.getMetaState();
                     ted.mReprocess = mDeferTouchProcess;
-                    mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
-                    mLastSentTouchTime = eventTime;
                     if (mDeferTouchProcess) {
+                        ted.mViewX = x;
+                        ted.mViewY = y;
+                        mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
                         break;
                     }
+                    mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
                     if (firstMove && !inFullScreenMode()) {
                         mPrivateHandler.sendMessageDelayed(mPrivateHandler
                                 .obtainMessage(PREVENT_DEFAULT_TIMEOUT,
@@ -4866,6 +4872,10 @@ public class WebView extends AbsoluteLayout
                     ted.mY = contentY;
                     ted.mMetaState = ev.getMetaState();
                     ted.mReprocess = mDeferTouchProcess;
+                    if (mDeferTouchProcess) {
+                        ted.mViewX = x;
+                        ted.mViewY = y;
+                    }
                     mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
                 }
                 mLastTouchUpTime = eventTime;
@@ -4880,6 +4890,10 @@ public class WebView extends AbsoluteLayout
                             ted.mY = contentY;
                             ted.mMetaState = ev.getMetaState();
                             ted.mReprocess = mDeferTouchProcess;
+                            if (mDeferTouchProcess) {
+                                ted.mViewX = x;
+                                ted.mViewY = y;
+                            }
                             mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
                         } else if (mPreventDefault != PREVENT_DEFAULT_YES){
                             doDoubleTap();
@@ -6156,6 +6170,10 @@ public class WebView extends AbsoluteLayout
                         // simplicity for now, we don't set it.
                         ted.mMetaState = 0;
                         ted.mReprocess = mDeferTouchProcess;
+                        if (mDeferTouchProcess) {
+                            ted.mViewX = mLastTouchX;
+                            ted.mViewY = mLastTouchY;
+                        }
                         mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
                     } else if (mPreventDefault != PREVENT_DEFAULT_YES) {
                         mTouchMode = TOUCH_DONE_MODE;
@@ -6452,31 +6470,27 @@ public class WebView extends AbsoluteLayout
                         TouchEventData ted = (TouchEventData) msg.obj;
                         switch (ted.mAction) {
                             case MotionEvent.ACTION_DOWN:
-                                mLastDeferTouchX = contentToViewX(ted.mX)
-                                        - mScrollX;
-                                mLastDeferTouchY = contentToViewY(ted.mY)
-                                        - mScrollY;
+                                mLastDeferTouchX = ted.mViewX;
+                                mLastDeferTouchY = ted.mViewY;
                                 mDeferTouchMode = TOUCH_INIT_MODE;
                                 break;
                             case MotionEvent.ACTION_MOVE: {
                                 // no snapping in defer process
-                                int x = contentToViewX(ted.mX) - mScrollX;
-                                int y = contentToViewY(ted.mY) - mScrollY;
                                 if (mDeferTouchMode != TOUCH_DRAG_MODE) {
                                     mDeferTouchMode = TOUCH_DRAG_MODE;
-                                    mLastDeferTouchX = x;
-                                    mLastDeferTouchY = y;
+                                    mLastDeferTouchX = ted.mViewX;
+                                    mLastDeferTouchY = ted.mViewY;
                                     startDrag();
                                 }
                                 int deltaX = pinLocX((int) (mScrollX
-                                        + mLastDeferTouchX - x))
+                                        + mLastDeferTouchX - ted.mViewX))
                                         - mScrollX;
                                 int deltaY = pinLocY((int) (mScrollY
-                                        + mLastDeferTouchY - y))
+                                        + mLastDeferTouchY - ted.mViewY))
                                         - mScrollY;
                                 doDrag(deltaX, deltaY);
-                                if (deltaX != 0) mLastDeferTouchX = x;
-                                if (deltaY != 0) mLastDeferTouchY = y;
+                                if (deltaX != 0) mLastDeferTouchX = ted.mViewX;
+                                if (deltaY != 0) mLastDeferTouchY = ted.mViewY;
                                 break;
                             }
                             case MotionEvent.ACTION_UP:
@@ -6489,8 +6503,8 @@ public class WebView extends AbsoluteLayout
                                 break;
                             case WebViewCore.ACTION_DOUBLETAP:
                                 // doDoubleTap() needs mLastTouchX/Y as anchor
-                                mLastTouchX = contentToViewX(ted.mX) - mScrollX;
-                                mLastTouchY = contentToViewY(ted.mY) - mScrollY;
+                                mLastTouchX = ted.mViewX;
+                                mLastTouchY = ted.mViewY;
                                 doDoubleTap();
                                 mDeferTouchMode = TOUCH_DONE_MODE;
                                 break;
diff --git a/core/java/android/webkit/WebViewCore.java b/core/java/android/webkit/WebViewCore.java
index 625e7ba..0175aed 100644
--- a/core/java/android/webkit/WebViewCore.java
+++ b/core/java/android/webkit/WebViewCore.java
@@ -708,6 +708,8 @@ final class WebViewCore {
         int mY;
         int mMetaState;
         boolean mReprocess;
+        float mViewX;
+        float mViewY;
     }
 
     static class GeolocationPermissionsData {