Add missing schemes to RecordMainFrameNavigation

components/navigation_metrics/navigation_metrics.cc

Index: components/navigation_metrics/navigation_metrics.cc
diff --git a/components/navigation_metrics/navigation_metrics.cc b/components/navigation_metrics/navigation_metrics.cc
index 78df32462d84c6b20fdd45000e4f77c56bea629d..b230f174ec2dee8509f5b5b62d0e171bb4d83dbf 100644
--- a/components/navigation_metrics/navigation_metrics.cc
+++ b/components/navigation_metrics/navigation_metrics.cc
@@ -10,20 +10,23 @@
 
 namespace {
 
-// This enum is used in building the histogram. So, this is append only,
-// any new scheme should be added at the end, before SCHEME_MAX
+// These values are written to logs. New enum values can be added, but existing
+// enums must never be renumbered or deleted and reused. Any new scheme should
+// be added at the end, before SCHEME_MAX.
 enum Scheme {
-  SCHEME_UNKNOWN,
-  SCHEME_HTTP,
-  SCHEME_HTTPS,
-  SCHEME_FILE,
-  SCHEME_FTP,
-  SCHEME_DATA,
-  SCHEME_JAVASCRIPT,
-  SCHEME_ABOUT,
-  SCHEME_CHROME,
-  SCHEME_BLOB,
-  SCHEME_FILESYSTEM,
+  SCHEME_UNKNOWN = 0,
+  SCHEME_HTTP = 1,
+  SCHEME_HTTPS = 2,
+  SCHEME_FILE = 3,
+  SCHEME_FTP = 4,
+  SCHEME_DATA = 5,
+  SCHEME_JAVASCRIPT = 6,
+  SCHEME_ABOUT = 7,
+  SCHEME_CHROME = 8,
+  SCHEME_BLOB = 9,
+  SCHEME_FILESYSTEM = 10,
+  SCHEME_CHROMENATIVE = 11,

[Mark P, 2017/06/28 16:25:19]

optional nit: SCHEME_CHROMENATIVE is hard to parse for me.  Consider
SCHEME_CHROME_NATIVE
analogous comment below

[elawrence, 2017/06/28 17:03:40]

Fixed, thanks.

+  SCHEME_CHROMESEARCH = 12,
   SCHEME_MAX,
 };
 
@@ -39,6 +42,8 @@ const char* const kSchemeNames[] = {
     "chrome",
     url::kBlobScheme,
     url::kFileSystemScheme,
+    "chrome-native",
+    "chrome-search",
     "max",
 };