[Offline pages] Clean up unnecessary DeleteAll calls in offline internals

chrome/browser/resources/offline_pages/offline_internals.html

Index: chrome/browser/resources/offline_pages/offline_internals.html
diff --git a/chrome/browser/resources/offline_pages/offline_internals.html b/chrome/browser/resources/offline_pages/offline_internals.html
index 6ba2f41a27cdd99fcb39d4f860f7124e53fdc9aa..93f5aed265185369cb867ac7b12430ee2cb919fd 100644
--- a/chrome/browser/resources/offline_pages/offline_internals.html
+++ b/chrome/browser/resources/offline_pages/offline_internals.html
@@ -40,8 +40,8 @@
 
     <h2>Stored Pages</h2>
     <div>
-      <button id="clear-all">Clear all</button>
-      <button id="clear-selected">Clear selected</button>
+      <button id="delete-all-pages">Clear all</button>

[dewittj, 2016/09/14 18:39:10]

nit: why move to "delete" when the model uses "clear" for this action?

[chili, 2016/09/14 18:47:07]

Request queue uses delete (line 62-63).  Whenever I see 'clear' here and
'delete' in request queue, I would wonder if there's some fundamental difference
between 'delete' and 'clear', and I'd be tempted to make them the same.

I will update the button text as well (missed that)

+      <button id="delete-selected-pages">Clear selected</button>
     </div>
     <table class="stored-pages-table">
       <thead>