fix a weird use of Vector::appendVector()

operator= is way more efficient.

Change-Id: I61c9adb1413bed230801a77151b8f7000fd11471
diff --git a/services/input/InputDispatcher.cpp b/services/input/InputDispatcher.cpp
index 10b9083..da9b55c 100644
--- a/services/input/InputDispatcher.cpp
+++ b/services/input/InputDispatcher.cpp
@@ -3154,11 +3154,9 @@
             mLastHoverWindow = NULL;
         }
 
-        mWindows.clear();
-
         // Loop over new windows and rebuild the necessary window pointers for
         // tracking focus and touch.
-        mWindows.appendVector(inputWindows);
+        mWindows = inputWindows;
 
         size_t numWindows = mWindows.size();
         for (size_t i = 0; i < numWindows; i++) {
@@ -4560,8 +4558,7 @@
     split = other.split;
     deviceId = other.deviceId;
     source = other.source;
-    windows.clear();
-    windows.appendVector(other.windows);
+    windows = other.windows;
 }
 
 void InputDispatcher::TouchState::addOrUpdateWindow(const InputWindow* window,