Add GetTimeTicksNow() to PlatformSupport.

mojo/edk/system/test_utils.h

Index: mojo/edk/system/test_utils.h
diff --git a/mojo/edk/system/test_utils.h b/mojo/edk/system/test_utils.h
index 59f9dd53bbf387d3674af8949c4d880e89b6cd90..8d424cc9e9092dce334df0b6eafad374e191de08 100644
--- a/mojo/edk/system/test_utils.h
+++ b/mojo/edk/system/test_utils.h
@@ -5,7 +5,7 @@
 #ifndef MOJO_EDK_SYSTEM_TEST_UTILS_H_
 #define MOJO_EDK_SYSTEM_TEST_UTILS_H_
 
-#include "base/time/time.h"
+#include "mojo/edk/embedder/simple_platform_support.h"
 #include "mojo/public/c/system/types.h"
 #include "mojo/public/cpp/system/macros.h"
 
@@ -55,7 +55,11 @@ class Stopwatch {
   MojoDeadline Elapsed();
 
  private:
-  base::TimeTicks start_time_;
+  // TODO(vtl): We need this for |GetTimeTicksNow()|. Maybe we should have a
+  // singleton for tests instead? Or maybe it should be injected?
+  embedder::SimplePlatformSupport platform_support_;
+
+  MojoTimeTicks start_time_;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(Stopwatch);
 };