Rename Tab.LockIcon to Tab.SecurityState

The tab's state is concerned with whether or not the page is secure. It should
not mention the lock icon, as this is just a UI choice of how to represent the
security state.

Also renames WebViewController.onUpdatedLockIcon() to onUpdatedSecurityState().

No functional change.

Bug: 5403366
Change-Id: Id18402e84fd9b1f661c160189c7a19a9352fd25c
diff --git a/src/com/android/browser/WebViewController.java b/src/com/android/browser/WebViewController.java
index f4ff764..20027e0 100644
--- a/src/com/android/browser/WebViewController.java
+++ b/src/com/android/browser/WebViewController.java
@@ -95,7 +95,7 @@
 
     boolean shouldShowErrorConsole();
 
-    void onUpdatedLockIcon(Tab tab);
+    void onUpdatedSecurityState(Tab tab);
 
     void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType);