Add filesystem scheme to navigation histograms.

BUG=594215

Review-Url: https://codereview.chromium.org/2476993002
Cr-Commit-Position: refs/heads/master@{#430346}

components/navigation_metrics/navigation_metrics.cc

@@ -23,6 +23,7 @@ enum Scheme {
   SCHEME_ABOUT,
   SCHEME_CHROME,
   SCHEME_BLOB,
+  SCHEME_FILESYSTEM,
   SCHEME_MAX,
 };
 
@@ -37,6 +38,7 @@ const char* const kSchemeNames[] = {
     url::kAboutScheme,
     "chrome",
     url::kBlobScheme,
+    url::kFileSystemScheme,
     "max",
 };
 

tools/metrics/histograms/histograms.xml

@@ -92941,6 +92941,7 @@ value.
   <int value="7" label="about"/>
   <int value="8" label="chrome"/>
   <int value="9" label="blob"/>
+  <int value="10" label="filesystem"/>
 </enum>
 
 <enum name="NavigatorVibrationType" type="int">