Bug 679966, part 2: Add mozVibrator() for "playing" a vibration pattern. r=bz

hal/android/AndroidHal.cpp

@@ -50,16 +50,28 @@ Vibrate(const nsTArray<uint32> &pattern, const WindowIdentifier &)
   // hal_sandbox::Vibrate, and hal_impl::Vibrate all must have the same
   // signature.
 
+  // Strangely enough, the Android Java API seems to treat vibrate([0]) as a
+  // nop.  But we want to treat vibrate([0]) like CancelVibrate!  (Note that we
+  // also need to treat vibrate([]) as a call to CancelVibrate.)
+  bool allZero = true;
+  for (uint32 i = 0; i < pattern.Length(); i++) {
+    if (pattern[i] != 0) {
+      allZero = false;
+      break;
+    }
+  }
+
+  if (allZero) {
+    hal_impl::CancelVibrate(WindowIdentifier());
+    return;
+  }
+
   AndroidBridge* b = AndroidBridge::Bridge();
   if (!b) {
     return;
   }
 
-  if (pattern.Length() == 0) {
-    b->CancelVibrate();
-  } else {
-    b->Vibrate(pattern);
-  }
+  b->Vibrate(pattern);
 }
 
 void