Make backdrop fully opaque

ash/common/wm/maximize_mode/workspace_backdrop_delegate.cc

Index: ash/common/wm/maximize_mode/workspace_backdrop_delegate.cc
diff --git a/ash/common/wm/maximize_mode/workspace_backdrop_delegate.cc b/ash/common/wm/maximize_mode/workspace_backdrop_delegate.cc
index 51113c24500eb035a3f8129279c1dc8184932a86..ccf3c4f66c003b5dcca39a939d1a51c8da0693cd 100644
--- a/ash/common/wm/maximize_mode/workspace_backdrop_delegate.cc
+++ b/ash/common/wm/maximize_mode/workspace_backdrop_delegate.cc
@@ -21,7 +21,7 @@ namespace ash {
 namespace {
 
 // The opacity of the backdrop.
-const float kBackdropOpacity = 0.5f;
+const float kBackdropOpacity = 1.0f;
 
 }  // namespace