[Android] Ensure MotionEvents are always recycled

There were several cases in ContentViewCore where a MotionEvent was obtained
(copied) for offsetting purposes, but was not recycled because of early function
exit. Fix this by recycling the event in the finally clause. Also avoid copying
touch events if the current touch offset is zero.

Review URL: https://codereview.chromium.org/263833013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@267980 0039d316-1c4b-4281-b951-d872f2087c98

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

@@ -1081,36 +1081,48 @@ public class ContentViewCore
      * @see View#onTouchEvent(MotionEvent)
      */
     public boolean onTouchEvent(MotionEvent event) {
-        MotionEvent offset = createOffsetMotionEvent(event);
+        TraceEvent.begin("onTouchEvent");
+        try {
+            cancelRequestToScrollFocusedEditableNodeIntoView();
+
+            final int eventAction = event.getActionMasked();
+
+            // Only these actions have any effect on gesture detection.  Other
+            // actions have no corresponding WebTouchEvent type and may confuse the
+            // touch pipline, so we ignore them entirely.
+            if (eventAction != MotionEvent.ACTION_DOWN
+                    && eventAction != MotionEvent.ACTION_UP
+                    && eventAction != MotionEvent.ACTION_CANCEL
+                    && eventAction != MotionEvent.ACTION_MOVE
+                    && eventAction != MotionEvent.ACTION_POINTER_DOWN
+                    && eventAction != MotionEvent.ACTION_POINTER_UP) {
+                return false;
+            }
 
-        cancelRequestToScrollFocusedEditableNodeIntoView();
+            if (mNativeContentViewCore == 0) return false;
 
-        final int eventAction = offset.getActionMasked();
+            // A zero offset is quite common, in which case the unnecessary copy should be avoided.
+            MotionEvent offset = null;
+            if (mCurrentTouchOffsetX != 0 || mCurrentTouchOffsetY != 0) {
+                offset = createOffsetMotionEvent(event);
+                event = offset;
+            }
 
-        // Only these actions have any effect on gesture detection.  Other
-        // actions have no corresponding WebTouchEvent type and may confuse the
-        // touch pipline, so we ignore them entirely.
-        if (eventAction != MotionEvent.ACTION_DOWN
-                && eventAction != MotionEvent.ACTION_UP
-                && eventAction != MotionEvent.ACTION_CANCEL
-                && eventAction != MotionEvent.ACTION_MOVE
-                && eventAction != MotionEvent.ACTION_POINTER_DOWN
-                && eventAction != MotionEvent.ACTION_POINTER_UP) {
-            return false;
+            final int pointerCount = event.getPointerCount();
+            final boolean consumed = nativeOnTouchEvent(mNativeContentViewCore, event,
+                    event.getEventTime(), eventAction,
+                    pointerCount, event.getHistorySize(), event.getActionIndex(),
+                    event.getX(), event.getY(),
+                    pointerCount > 1 ? event.getX(1) : 0,
+                    pointerCount > 1 ? event.getY(1) : 0,
+                    event.getPointerId(0), pointerCount > 1 ? event.getPointerId(1) : -1,
+                    event.getTouchMajor(), pointerCount > 1 ? event.getTouchMajor(1) : 0);
+
+            if (offset != null) offset.recycle();
+            return consumed;
+        } finally {
+            TraceEvent.end("onTouchEvent");
         }
-
-        if (mNativeContentViewCore == 0) return false;
-        final int pointerCount = offset.getPointerCount();
-        boolean consumed = nativeOnTouchEvent(mNativeContentViewCore, offset,
-                offset.getEventTime(), eventAction,
-                pointerCount, offset.getHistorySize(), offset.getActionIndex(),
-                offset.getX(), offset.getY(),
-                pointerCount > 1 ? offset.getX(1) : 0,
-                pointerCount > 1 ? offset.getY(1) : 0,
-                offset.getPointerId(0), pointerCount > 1 ? offset.getPointerId(1) : -1,
-                offset.getTouchMajor(), pointerCount > 1 ? offset.getTouchMajor(1) : 0);
-        offset.recycle();
-        return consumed;
     }
 
     public void setIgnoreRemainingTouchEvents() {
@@ -1613,25 +1625,27 @@ public class ContentViewCore
     public boolean onHoverEvent(MotionEvent event) {
         TraceEvent.begin("onHoverEvent");
         MotionEvent offset = createOffsetMotionEvent(event);
+        try {
+            if (mBrowserAccessibilityManager != null) {
+                return mBrowserAccessibilityManager.onHoverEvent(offset);
+            }
 
-        if (mBrowserAccessibilityManager != null) {
-            return mBrowserAccessibilityManager.onHoverEvent(offset);
-        }
+            // Work around Android bug where the x, y coordinates of a hover exit
+            // event are incorrect when touch exploration is on.
+            if (mTouchExplorationEnabled && offset.getAction() == MotionEvent.ACTION_HOVER_EXIT) {
+                return true;
+            }
 
-        // Work around Android bug where the x, y coordinates of a hover exit
-        // event are incorrect when touch exploration is on.
-        if (mTouchExplorationEnabled && offset.getAction() == MotionEvent.ACTION_HOVER_EXIT) {
+            mContainerView.removeCallbacks(mFakeMouseMoveRunnable);
+            if (mNativeContentViewCore != 0) {
+                nativeSendMouseMoveEvent(mNativeContentViewCore, offset.getEventTime(),
+                        offset.getX(), offset.getY());
+            }
             return true;
+        } finally {
+            offset.recycle();
+            TraceEvent.end("onHoverEvent");
         }
-
-        mContainerView.removeCallbacks(mFakeMouseMoveRunnable);
-        if (mNativeContentViewCore != 0) {
-            nativeSendMouseMoveEvent(mNativeContentViewCore, offset.getEventTime(),
-                    offset.getX(), offset.getY());
-        }
-        TraceEvent.end("onHoverEvent");
-        offset.recycle();
-        return true;
     }
 
     /**
@@ -1653,6 +1667,7 @@ public class ContentViewCore
                         @Override
                         public void run() {
                             onHoverEvent(eventFakeMouseMove);
+                            eventFakeMouseMove.recycle();
                         }
                     };
                     mContainerView.postDelayed(mFakeMouseMoveRunnable, 250);