[Android WebView] Suppress overscroll pulls

When there is no touch event taking place, suppress calls to onPull
that may come in after the users finger has left the screen.

BUG=391464

Review URL: https://codereview.chromium.org/366283004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@281432 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 15 insertions, 2 deletions

diff --git a/android_webview/java/src/org/chromium/android_webview/AwContents.java b/android_webview/java/src/org/chromium/android_webview/AwContents.java
index 61c392c..8497489 100644
--- a/android_webview/java/src/org/chromium/android_webview/AwContents.java
+++ b/android_webview/java/src/org/chromium/android_webview/AwContents.java
@@ -2274,8 +2274,14 @@ public class AwContents {
                         (int) Math.round(event.getY(actionIndex) / mDIPScale));
             }
 
-            if (mOverScrollGlow != null && event.getActionMasked() == MotionEvent.ACTION_UP) {
-                mOverScrollGlow.releaseAll();
+            if (mOverScrollGlow != null) {
+                if (event.getActionMasked() == MotionEvent.ACTION_DOWN) {
+                    mOverScrollGlow.setShouldPull(true);
+                } else if (event.getActionMasked() == MotionEvent.ACTION_UP ||
+                        event.getActionMasked() == MotionEvent.ACTION_CANCEL) {
+                    mOverScrollGlow.setShouldPull(false);
+                    mOverScrollGlow.releaseAll();
+                }
             }
 
             return rv;
diff --git a/android_webview/java/src/org/chromium/android_webview/OverScrollGlow.java b/android_webview/java/src/org/chromium/android_webview/OverScrollGlow.java
index 958da9d..2ebc198 100644
--- a/android_webview/java/src/org/chromium/android_webview/OverScrollGlow.java
+++ b/android_webview/java/src/org/chromium/android_webview/OverScrollGlow.java
@@ -23,6 +23,8 @@ class OverScrollGlow {
     private int mOverScrollDeltaX;
     private int mOverScrollDeltaY;
 
+    private boolean mShouldPull;
+
     public OverScrollGlow(Context context, View host) {
         mHostView = host;
         mEdgeGlowTop = new EdgeEffect(context);
@@ -31,6 +33,10 @@ class OverScrollGlow {
         mEdgeGlowRight = new EdgeEffect(context);
     }
 
+    public void setShouldPull(boolean shouldPull) {
+        mShouldPull = shouldPull;
+    }
+
     /**
      * Pull leftover touch scroll distance into one of the edge glows as appropriate.
      *
@@ -42,6 +48,7 @@ class OverScrollGlow {
      * @param maxY Maximum range for vertical scrolling
      */
     public void pullGlow(int x, int y, int oldX, int oldY, int maxX, int maxY) {
+        if (!mShouldPull) return;
         // Only show overscroll bars if there was no movement in any direction
         // as a result of scrolling.
         if (oldX == mHostView.getScrollX() && oldY == mHostView.getScrollY()) {