[view-compiler] Better namespacing of util functions

This moves some helper functions into our own namespace to avoid conflicting
with other util.h files.

Bug: 111895153
Change-Id: I2b4c77732a97b34a8528d69867c15ed802686703
diff --git a/startop/view_compiler/util.cc b/startop/view_compiler/util.cc
index 69df41d..a0637e6 100644
--- a/startop/view_compiler/util.cc
+++ b/startop/view_compiler/util.cc
@@ -18,6 +18,9 @@
 
 using std::string;
 
+namespace startop {
+namespace util {
+
 // TODO: see if we can borrow this from somewhere else, like aapt2.
 string FindLayoutNameFromFilename(const string& filename) {
   size_t start = filename.rfind("/");
@@ -30,3 +33,6 @@
 
   return filename.substr(start, end - start);
 }
+
+}  // namespace util
+}  // namespace startop