[Password Manager] Add UMA stats for submitted form type

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 98be29cefe59e1a83d403a6e1fd2beb066e5c632..13342a58e60a4490c3badb87e575d9d6b508311c 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -25294,6 +25294,16 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="PasswordManager.SubmittedFormType" enum="PasswordFormType">
+  <owner>gcasto@chromium.org</owner>
+  <owner>vabr@chromium.org</owner>
+  <summary>
+    The type (e.g. signup, login, change password) of all submitted password
+    forms. This is logged on form submission, but doesn't require that the
+    password manager saves.
+  </summary>
+</histogram>
+
 <histogram name="PasswordManager.SyncCredentialFiltered" enum="Boolean">
   <owner>gcasto@chromium.org</owner>
   <owner>vabr@chromium.org</owner>
@@ -56903,6 +56913,19 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="1" label="Current query"/>
 </enum>
 
+<enum name="PasswordFormType" type="int">
+  <int value="0" label="Login form"/>
+  <int value="1" label="Login form without username"/>
+  <int value="2"
+      label="Enabled change password form (saved credentials match username)"/>
+  <int value="3"
+      label="Disabled change password form (no matching credentials)"/>
+  <int value="4" label="Disabled change password form without username"/>
+  <int value="5" label="Signup form"/>
+  <int value="6" label="Signup form without username"/>
+  <int value="7" label="Combined login and signup form"/>
+</enum>
+
 <enum name="PasswordGenerationEvent" type="int">
   <int value="0" label="No sign up form"/>
   <int value="1" label="Local heuristics found sign up form"/>