DevTools: fix minor UI issues

1. Disable pointer events in the HTML preview.
2. Fix font size in the IDB object store display header.

Change-Id: I0b19333c28392cc7641fb551aac9ab3deb27f1e1
Reviewed-on: https://chromium-review.googlesource.com/990207
Reviewed-by: Andrey Lushnikov <lushnikov@chromium.org>
Commit-Queue: Eugene Ostroukhov <eostroukhov@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#547558}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 0300fb5c41637ba7d2633d21dec29124d60e17cb
diff --git a/front_end/network/requestHTMLView.css b/front_end/network/requestHTMLView.css
index a71ebee..dac6625 100644
--- a/front_end/network/requestHTMLView.css
+++ b/front_end/network/requestHTMLView.css
@@ -7,4 +7,5 @@
   box-shadow: 0 1px 3px rgba(0, 0, 0, 0.5);
   flex-grow: 1;
   margin: 20px;
+  pointer-events: none;
 }
diff --git a/front_end/resources/indexedDBViews.css b/front_end/resources/indexedDBViews.css
index 5100428..58de433 100644
--- a/front_end/resources/indexedDBViews.css
+++ b/front_end/resources/indexedDBViews.css
@@ -84,6 +84,10 @@
     unicode-bidi: -webkit-isolate;
 }
 
+.source-code.indexed-db-key-path {
+    font-size: unset !important;
+}
+
 .resources-toolbar {
     padding-right: 10px;
 }