cc: Remove unnecessary "default" cases from switch statements.

cc/output/render_surface_filters.cc

Index: cc/output/render_surface_filters.cc
diff --git a/cc/output/render_surface_filters.cc b/cc/output/render_surface_filters.cc
index fa84e67f4d3913dd66ef067eb55d72e031c6cd20..04d8c5ab9f743c4c4e6b67bb902fb27e94a2af4f 100644
--- a/cc/output/render_surface_filters.cc
+++ b/cc/output/render_surface_filters.cc
@@ -226,9 +226,13 @@ bool GetColorMatrix(const FilterOperation& op, SkScalar matrix[20]) {
       memcpy(matrix, op.matrix(), sizeof(SkScalar[20]));
       return true;
     }
-    default:
+    case FilterOperation::BLUR:
+    case FilterOperation::DROP_SHADOW:
+    case FilterOperation::ZOOM:
       return false;
   }
+  NOTREACHED();
+  return false;
 }
 
 class FilterBufferState {