Enable precise memory info in layout tests

content/shell/app/shell_main_delegate.cc

Index: content/shell/app/shell_main_delegate.cc
diff --git a/content/shell/app/shell_main_delegate.cc b/content/shell/app/shell_main_delegate.cc
index 3eecb830eaf6a73683928eb0fbe8d4a93b17c13b..b7aeb6be28f0b707bbf913667a297f70293114f0 100644
--- a/content/shell/app/shell_main_delegate.cc
+++ b/content/shell/app/shell_main_delegate.cc
@@ -170,6 +170,8 @@ bool ShellMainDelegate::BasicStartupComplete(int* exit_code) {
 
     command_line.AppendSwitch(switches::kEnableFileCookies);
 
+    command_line.AppendSwitch(switches::kEnablePreciseMemoryInfo);
+
     // Unless/until WebM files are added to the media layout tests, we need to
     // avoid removing MP4/H264/AAC so that layout tests can run on Android.
 #if !defined(OS_ANDROID)