Fix Extensions.AppLaunchSource off-by-one error

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index c7efa544e9762a5a207b8e61e5bf621dbca5065f..69b9bd5338dc6e8da7e202708f97cdaeee0d6a7a 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -74144,26 +74144,27 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </enum>
 
 <enum name="AppLaunchSource" type="int">
-  <int value="0" label="SOURCE_UNTRACKED"/>
-  <int value="1" label="SOURCE_APP_LAUNCHER"/>
-  <int value="2" label="SOURCE_NEW_TAB_PAGE"/>
-  <int value="3" label="SOURCE_RELOAD"/>
-  <int value="4" label="SOURCE_RESTART"/>
-  <int value="5" label="SOURCE_LOAD_AND_LAUNCH"/>
-  <int value="6" label="SOURCE_COMMAND_LINE"/>
-  <int value="7" label="SOURCE_FILE_HANDLER"/>
-  <int value="8" label="SOURCE_URL_HANDLER"/>
-  <int value="9" label="SOURCE_SYSTEM_TRAY"/>
-  <int value="10" label="SOURCE_ABOUT_PAGE"/>
-  <int value="11" label="SOURCE_KEYBOARD"/>
-  <int value="12" label="SOURCE_EXTENSIONS_PAGE"/>
-  <int value="13" label="SOURCE_MANAGEMENT_API"/>
-  <int value="14" label="SOURCE_EPHEMERAL_APP_DEPRECATED"/>
-  <int value="15" label="SOURCE_BACKGROUND"/>
-  <int value="16" label="SOURCE_KIOSK"/>
-  <int value="17" label="SOURCE_CHROME_INTERNAL"/>
-  <int value="18" label="SOURCE_TEST"/>
-  <int value="19" label="SOURCE_INSTALLED_NOTIFICATION"/>
+  <int value="0" label="LAUNCH_SOURCE_NONE"/>
+  <int value="1" label="LAUNCH_SOURCE_UNTRACKED"/>
+  <int value="2" label="LAUNCH_SOURCE_APP_LAUNCHER"/>
+  <int value="3" label="LAUNCH_SOURCE_NEW_TAB_PAGE"/>
+  <int value="4" label="LAUNCH_SOURCE_RELOAD"/>
+  <int value="5" label="LAUNCH_SOURCE_RESTART"/>
+  <int value="6" label="LAUNCH_SOURCE_LOAD_AND_LAUNCH"/>
+  <int value="7" label="LAUNCH_SOURCE_COMMAND_LINE"/>
+  <int value="8" label="LAUNCH_SOURCE_FILE_HANDLER"/>
+  <int value="9" label="LAUNCH_SOURCE_URL_HANDLER"/>
+  <int value="10" label="LAUNCH_SOURCE_SYSTEM_TRAY"/>
+  <int value="11" label="LAUNCH_SOURCE_ABOUT_PAGE"/>
+  <int value="12" label="LAUNCH_SOURCE_KEYBOARD"/>
+  <int value="13" label="LAUNCH_SOURCE_EXTENSIONS_PAGE"/>
+  <int value="14" label="LAUNCH_SOURCE_MANAGEMENT_API"/>
+  <int value="15" label="LAUNCH_SOURCE_EPHEMERAL_APP"/>
+  <int value="16" label="LAUNCH_SOURCE_BACKGROUND"/>
+  <int value="17" label="LAUNCH_SOURCE_KIOSK"/>
+  <int value="18" label="LAUNCH_SOURCE_CHROME_INTERNAL"/>
+  <int value="19" label="LAUNCH_SOURCE_TEST"/>
+  <int value="20" label="LAUNCH_SOURCE_INSTALLED_NOTIFICATION"/>
 </enum>
 
 <enum name="AppleScriptCommandEvents" type="int">